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A flaw in the OpenCode AI coding agent allowed a malicious or hijacked MCP server to run code on a developer's Windows or WSL machine when the developer signed in. OpenCode connects to MCP (Model Context Protocol) servers to add outside tools, and such code would run with the developer's own access. Anomaly , the company behind OpenCode, fixed the flaw in  version 1.18.33  on September 28. It did not request a CVE or publish a security advisory, so vulnerability scanners will not flag the builds still at risk: 1.0.137 through 1.18.32. During that sign-in, the server itself supplies the web address the user is sent to, an OAuth "authorization endpoint." On Windows and WSL, OpenCode handed that address to a helper that opens it in a browser. The helper built a PowerShell command around the address without escaping it, so an address written to carry a PowerShell command would run that command. The browser step runs only when a developer starts the sign-in, by ru...

Node.js released  security updates  on October 21 for its three supported release lines, 22.x, 24.x and 26.x, fixing 10 flaws. The most serious is a bug in the Brotli decompression code that Node.js bundles, which the project says can allow remote code execution, meaning an attacker could run code of their choosing on the affected system. Each supported line has one fixed version:  22.23.4  and  24.22.1  on the long-term support lines, and  26.12.1  on the current line. Node.js 20.x and earlier have  reached end of life  and will not receive the fix, so they should be moved to a supported line. The Brotli flaw is in code Node.js bundles, not in a user's own program. Node.js runs that code whenever it decompresses Brotli data, either directly through the  node:zlib  module or automatically when code calls fetch() on a response sent with Brotli compression. An application is exposed where it decompresses Brotli data an att...

A remote attacker who has not logged in can crash many HTTP/3 web servers with a single connection, security firm FoxIO  disclosed , releasing working proof-of-concept code. By sending a small batch of compressed HTTP headers that expands in memory to a much larger set, the attacker can force the server to use thousands of times more memory than it received, enough to run a default server out of memory. The flaws cause only denial-of-service attacks, with no evidence of data theft or code execution and no public reports of attacks in the wild. Fixes are out for quic-go, Cloudflare quiche, lsquic and Wireshark, but Bun, the h3 Rust library and aioquic were still unpatched at disclosure. FoxIO found the same class of flaw in seven of ten HTTP/3 stacks it tested. The common cause is in QPACK, the scheme HTTP/3 uses to compress request headers so repeated fields travel as a short code instead of the full text. A server is supposed to cap the size of the headers after it unpack...

Amazon's Threat Intelligence team on Wednesday said it detected an attempt to exploit the newly disclosed PHP2Shell vulnerabilities on October 17, 2026, against its MadPot honeypot service, as the flaws come under broad exploitation in the wild following the release of the patches. "The exploit attempt originated from an IP address associated with a commercial anonymization network," CJ Moses, CISO of Amazon Integrated Security, said in a post shared with The Hacker News. "While the vulnerability was under embargo, the targeting of a honeypot from an anonymized IP address suggests the activity was conducted by a threat actor, though it remains unclear how the actor acquired exploit information prior to disclosure." The attempt, Amazon said, was recorded from " 103.216.220[.]92 ," an IP address geolocated to Australia. The activity relates to a set of two vulnerabilities impacting PHP core, both rated 9.2 on the CVSS scoring system. Tracked ...

GitLab released fixes on October 21 for a flaw that lets an attacker run code on a self-managed server without logging in, and it affects every version of the software going back to 7.0, released in 2014. The fix matters even for administrators who patched nine days earlier: the October 12 update covered only versions 19.2 and later, and the new fixed versions sit one patch above it, so an instance updated then is in range again. The flaw, tracked as  CVE-2026-110264 , is rated 10.0 on the CVSS scale, the maximum. GitLab says that, under certain conditions, it could allow an unauthenticated user to run arbitrary code on the server due to an integer overflow during the compilation of a specially crafted regular expression. GitLab has not said what those conditions are. The company reports no sign the flaw has been used in attacks, and it is not listed in the U.S. CISA catalog of known exploited vulnerabilities as of October 22. Only self-managed installations need to act. G...

PHP has released emergency updates that fix two critical flaws in the language itself, letting an attacker without an account run code on a web server. The fixes are in PHP 8.5.12, 8.4.27, 8.3.36 and 8.2.35, and the PHP team says only updating fully protects a server. The flaws, together called PHP2Shell , sit in the PHP runtime, not in any application, so a site is exposed even when its own code is secure. The risk is highest on servers using Apache's mod_php, where a working exploit triggers the attack before any application code runs. Both flaws are rated 9.2 on the CVSS v4.0 scale and carry the identifiers  CVE-2026-109618  and  CVE-2026-109619 . PHP published them around the scheduled release time of 14:00 UTC on October 21, a day after details leaked ahead of a planned October 22 disclosure. Researchers at Wiz, Calif, and OpenAI found and reported the flaws, which affect nearly every PHP version back to PHP 5.4. Who Is Affected Every PHP installatio...

You cannot fully block the two critical PHP flaws called PHP2Shell before today's fix, and the one setting being passed around as a workaround is not enough on its own, the security firm that suggested it now says. PHP will release the fix at  14:00 UTC on October 21  for two flaws it rates 9.2 out of 10, and has given no workaround of its own. Until you can install it, what lowers your risk is taking exposed PHP off the internet or behind access controls, cutting what a compromised server can reach, and having the update ready to apply the moment it lands. Cloudflare says it is seeing early attempts to exploit the flaws, and has pushed emergency rules for sites behind it that it calls a stopgap until you patch. No compromise has been confirmed, the public exploit code going around has not been shown to work, and neither flaw is in CISA's catalog of known exploited flaws. PHP has not said which versions are affected, which part of PHP is involved, or whether any setting ...

An AppSec team can point an AI agent running on a general-purpose model at its own web apps with little setup. Sure, the model writes the attacks. But everything that makes those attacks safe to run against production and worth acting on afterward lives in the harness around the model. The harness is where the engineering in AI pentesting sits. The Hugging Face intrusion OpenAI disclosed in July showed what happens when that harness gives way, even inside an OpenAI evaluation built to contain the agents. Why Each Control Takes Rigorous Engineering Let’s take a closer look at the attack different stages and the role AI agents can take there Scope A pentesting agent makes thousands of decisions about where to send its next request, and the model judges each one against a rule written in plain language. A web app’s real boundary often extends past one domain through redirects and calls to outside services. Enforcing scope means code that inspects every request before it leaves, a...

This story is developing and was written before PHP's scheduled 14:00 UTC release on October 21. Once the release is out, the affected and fixed versions below are confirmed by the official advisory. PHP will ship an out-of-cycle security release at 14:00 UTC today, October 21, for two critical vulnerabilities that its security team has rated 9.2 on the CVSS v4.0 scale but has not described. ⚡ UPDATE — PHP Issues Emergency Patches for Two Critical PHP2Shell RCE Flaws as Exploit Attempts Emerge Security researchers at watchTowr say the two flaws allow remote code execution. Only the four supported PHP branches, 8.2 through 8.5, can receive the fix, and no exploitation has been reported so far. The  advance notice  followed a leak. On October 20, a  post on HN  said two PHP remote code execution flaws, rated CVSS 10.0 and affecting versions from PHP 5 onward, would be disclosed on Thursday, October 22. The poster said they had "no evidence beyond 'source: trus...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Tuesday added four vulnerabilities to its Known Exploited Vulnerabilities ( KEV ) catalog, including four vulnerabilities impacting Plex Media Server that's collectively called Plex2Shell . The vulnerabilities are listed below - CVE-2026-96652 (CVSS score: 5.3) - Plex Media Server Server-Side Request Forgery (SSRF) vulnerability CVE-2026-96654 (CVSS score: 6.9) - Plex Media Server improper neutralization of encoded URI schemes in a web page Vulnerability CVE-2026-96655 (CVSS score: 5.3) - Plex Media Server Server-Side Request Forgery (SSRF) vulnerability CVE-2026-96656 (CVSS score: 8.6) - Plex Media Server external control of file name or path Vulnerability According to security researcher Zach Main, who discovered and reported the vulnerabilities, a remote attacker could chain the four vulnerabilities to achieve unauthenticated remote code execution. The issues were addressed in Plex Media ...

The private keys of eight eMudhra intermediate certificate authority (CA) certificates are compromised,  Mozilla  and  Google's Chrome Root Program  confirms on October 20. An intermediate CA signs the certificates that websites present, so anyone holding one of these keys could issue a certificate for any website that a browser would accept. A researcher reported the compromise to the root programs on the evening of October 17, and Chrome and Firefox blocked the eight certificates within hours, after Chrome verified the findings. No TLS certificate chaining to the six intermediates used for websites had been logged to  Certificate Transparency  (CT) before Chrome's block, so none could have been trusted by default in Chrome or any other browser that requires CT logging, the Chrome Root Program said. The keys did not have to be stolen. They were generated with too little randomness, so anyone can compute them from the public certificates,  Goo...

Cybersecurity researchers have released a proof-of-concept (PoC) exploit for a recently patched critical security flaw impacting Fortinet FortiSIEM that could result in arbitrary code execution. The vulnerability, tracked as CVE-2026-106173 (CVSS score: 9.4), is a critical path traversal flaw that could allow an unauthenticated attacker to execute unauthorized code or commands via specially crafted packets. Patches for the flaw were released last week by Fortinet in the following versions - FortiSIEM 7.5.0 (Upgrade to 7.5.1 or above) FortiSIEM 7.6 (Not affected) According to Horizon3.ai, the issue involves an unauthenticated attacker connecting to the gRPC service listening on TCP port 27918 and exploiting the flaw to overwrite an existing file outside of the intended directory and turn the arbitrary-file-write primitive into remote code execution. "The FortiSIEM gRPC QueryResultReq handler processes untrusted metadata without proper path validation," Horiz...

Palo Alto Networks has disclosed that it's continuing to observe exploitation of a now-patched security flaw impacting  PAN-OS and Prisma Access by ransomware actors. The activity relates to CVE-2026-0257 (CVSS score: 7.8), an authentication bypass flaw that could be exploited by bad actors to set up unauthorized VPN connections. It was patched by Palo Alto Networks in May 2026 and was added by the U.S. Cybersecurity and Infrastructure Security Agency (CSIA) to its Known Exploited Vulnerabilities (KEV) catalog on May 13, 2026. "Ransomware operators exploiting CVE-2026-0257 include Spikey Scorpius (aka Qilin) and Tarnished Scorpius (aka INC)," Unit 42 researchers said in an update shared on Monday. The development comes days after ReliaQuest said it detected both Qilin and Settra ransomware groups actively exploiting the flaw in financially-motivated attacks. According to Unit 42, the threat actors are weaponizing the flaw to gain an initial foothold into corpo...

A Chinese-speaking criminal pointed autonomous AI agents at company websites and let them break in with almost no help, and a security researcher watched it happen because the operators left their control panels open on the internet. The agents tried more than 1,200 sites and reached websites belonging to more than 100 companies, including farm-equipment maker Deere, appliance company SharkNinja and engine maker Cummins,  according to Reuters , which reviewed the attacker's own records to identify them. How much data, if any, was taken is not known. The researcher, Snorre Fagerland of the security firm NorForge , found the operations by scanning the internet for exposed copies of  Cairn , an open-source AI tool popular with hackers. Beginning around October 2, he found about two dozen Cairn instances being used maliciously, which let him read the attackers' work in real time. He set out the findings on Monday, and Reuters, which saw the report before publication, named...

The iPhone of Vladan Đokić, rector of the University of Belgrade and a prominent supporter of Serbia's student protest movement, was infected with NSO Group's Pegasus spyware in 2026, the  Citizen Lab said  on October 19. The finding came six days before Serbia's October 25 snap parliamentary election. The infection used a zero-click exploit, meaning Đokić did not have to tap a link or open a file for it to work. The lab found the infection with high confidence, but its note provides no date within 2026, does not identify who was behind the attack, and notes that its investigation is ongoing. The election was  called in September  after nearly two years of protests that began when a railway station canopy collapsed in Novi Sad in November 2024, killing 16 people. The Citizen Lab, a research group at the University of Toronto, analyzed forensic artifacts from the phone at Đokić's request, working with the Serbian digital-rights group SHARE Foundation. SHARE ...

Go 1.27.3 and Go 1.26.10, released on October 20, make Go's certificate verifier reject any certificate chain that passes through one of  eight intermediate certificate authority keys. Programs built on the new release will refuse connections to sites and services whose certificates were issued under those keys. The Go team says the keys belong to one certificate authority it has not named, and that it is blocking them because of "specific security concerns around their operation." It handled the fix on its  URGENT track , the one reserved for its most serious issues, and recommends upgrading immediately. Two days earlier, on October 17, Mozilla added six intermediate certificates issued by eMudhra's emSign Root TLS CA - G3 to  OneCRL , the list Firefox uses to block certificates. The Mozilla bug behind those entries is  closed to the public , and neither Mozilla nor Go has said what prompted its action. Whether Chrome, Apple, or Microsoft have taken simil...

The Russia-linked state-sponsored threat actor tracked as APT28 (aka BlueDelta, Fancy Bear, and Forest Blizzard) has been attributed to attacks targeting two member states of the North Atlantic Treaty Organization (NATO). The Symantec Threat Hunter Team, which is tracking the activity cluster under the moniker Swallowtail , involved the use of a backdoor called HOOKEDGE and a previously undocumented loader that is designed to decrypt and run an encrypted payload in memory by using a cryptographic key that's supplied at runtime. Targets of the activity included a law enforcement agency, a naval shipbuilder, and a manufacturer of military aircraft engines – entities that hold information that could be of use to a foreign intelligence agency, the Broadcom-owned threat intelligence unit said. "During one attack against the naval shipbuilder, operators returned to a compromised host repeatedly over the course of a week in what appeared to be hands-on-keyboard activity,...

Siemens has addressed a DLL sideloading vulnerability impacting Siemens Software Center that it said has been exploited in ClickFix attacks. The high-severity vulnerability, tracked as CVE-2026-110936 (CVSS v4 score: 8.4), could allow an attacker to place a specially-crafted DLL in a directory the application searches, resulting in execution of malicious code with the same privileges as the affected service. "The affected application loads dynamic-link libraries (DLLs) from an uncontrolled search path," Siemens said in an advisory. "This could allow an authenticated local attacker to place a specially crafted DLL in a directory that the application searches, leading to arbitrary code execution with the privileges of the affected application." The issue has been patched in version 4.0.9.8. Huntress Labs researcher Jose Oregon has been credited with discovering and reporting the shortcoming. In a separate alert, Siemens said attackers have abused a genuine ...

Threat actors have begun to exploit a chain of vulnerabilities in Plex Media Server to deploy cryptocurrency miners and reverse proxy software, a day after a proof-of-concept (PoC) went public. According to a researcher who goes by the online alias boredhackerblog , the exploitation activity involves chaining four different vulnerabilities, collectively called Plex2Shell . The vulnerabilities are below - CVE-2026-96652 (CVSS score: 5.3) - An unauthenticated server-side request forgery (SSRF) stemming via the "/player/timeline" endpoint by taking advantage of the fact that the "protocol" parameter is inserted into a programmatically-constructed player URL with no validation, allowing an attacker to force the Plex server to POST to a destination of their choice. CVE-2026-96654 (CVSS score: 6.9) - An improper neutralization of URL values included in the "searchOne" endpoint that could allow an attacker to call other plugins' functions and...

Copies of Rank Math PRO, the paid version of the Rank Math SEO plugin for WordPress, that were downloaded from rankmath.com or delivered as updates between 20:02 UTC on October 15 and 07:12 UTC on October 16 contained malware, Rank Math said in a  security notice  published on October 16. Any site that installed and activated one of those copies should be treated as compromised, and the malware can recreate its hidden backdoor whenever someone visits the site. Rank Math has removed the affected files and released a clean version, 3.0.124. Installing it replaces the plugin but does not remove files, administrator accounts, or scheduled tasks the malware may already have placed elsewhere on the server, Wordfence said in an  advisory  on October 17. Who Is Affected The version number does not show whether a copy is affected. Rank Math's  changelog  dates 3.0.123 to October 7, more than a week before the window opened, and the notice limits the inciden...