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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. It is not known how the keys left eMudhra, when, or whether anyone besides the researcher holds them. The keys are the ones Go blocked in its Octobe...

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...

The worst problems don't always come with a warning. Sometimes they arrive through a service everyone trusts, a device someone bought, or a system nobody thought to check. By the time something looks wrong, the damage may already be done. This week had plenty of that. Trusted connections became a problem. Hardware wasn't as safe as it looked. Old bugs found new victims, and some systems were left so exposed that breaking in barely required any effort. Even AI agents crossed lines they weren't supposed to. Some attacks were clever. Others were painfully simple. The full recap shows just how much can go wrong, and how little it sometimes takes. ⚡ Threat of the Week ConnectWise Suspends Cloud Backup Following Unauthorized Access — ConnectWise disabled seven ConnectWise application identities as it continues its investigation into an incident in which unknown threat actors obtained unauthorized access to the application identities and compromised Microsoft 365 tenant...

In Salesforce Agentforce, the recommended way to make an agent respond to events is a Flow: a record is created or a case is updated, and the Flow passes data into the agent's prompt. Separately, Email-to-Case and Web-to-Case turn inbound customer messages into case records; it is how airlines and hotels run support intake. Both are standard, documented, as-designed features. Chained together, they produce this path: public internet → email → case record → agent prompt → agent action → case comment → outbound reply An unauthenticated outsider now has a route into an internal agent's instructions, and the agent's reply leaves through the same door. Nothing was misconfigured. The finding, documented by researchers in August 2026, is a clean example of how agents that arrive inside existing platforms fail: through the application around them, not the model inside them. The risk is in the application, and the application is the thing nobody re-reviewed Which intake fea...

A flaw in Broadcom's Wi-Fi setup software lets an attacker within radio range run code as root on Broadcom-based routers, without the network password or any pairing step, security researcher Quentin Kaiser  disclosed  on October 16. He showed the attack working against home gateways supplied by three Belgian internet providers, in one case reading the Wi-Fi password off the device and in another opening a remote shell over the air. No CVE has been assigned to the flaw, and no fix has been deployed to the affected routers, Kaiser says. The flaw is in Broadcom's version of Wi-Fi Protected Setup (WPS), the feature that lets a device join a Wi-Fi network without the password being typed in. Broadcom's code mishandles the reassembly of fragmented WPS setup messages, so an attacker in range can send crafted messages that corrupt the router's memory. From there, Kaiser built two things: a way to read memory back off the device, and a way to run his own code on it. Ag...

A local privilege escalation exploit published today gains root on OpenBSD 7.9 by chaining a roughly 37-year-old integer overflow with a separate kernel flaw, bypassing OpenBSD's KARL kernel-address randomization and its SMAP and SMEP hardware protections. Security firm Calif, which found and reported the flaws, published a detailed writeup and full proof-of-concept code after OpenBSD shipped patches for both issues in September. The integer overflow in the shmat(4) attach function was fixed in errata 018 , shipped September 14 as a reliability fix. The reference-counting use-after-free that completes the chain was fixed separately in errata 026, shipped September 30 as a security fix. Both are available through syspatch and cover all architectures. OpenBSD 7.8 also received the integer-overflow fix. The integer overflow, the entry point for the full chain, is classified as a reliability fix, not a security fix. No CVE has been assigned for either flaw as of publication. ...

The China-nexus cyber espionage group tracked as Armory Castle (previously UNC5221 or Warp Panda) exploited a newly disclosed security flaw in BeyondTrust Remote Support (formerly Bomgar) as a zero-day in late August 2026. The vulnerability, tracked as CVE-2026-102764 (CVSS score: 9.3), is a case of improper origin validation in an internal messaging component that could be exploited by a remote attacker to perform file operations on an affected appliance. "The vulnerability exists within internal components of Remote Support," BeyondTrust said in a Thursday alert. "The components did not adequately validate the origin of the messages it received. Under the right conditions, this could be used to perform file operations on the appliance." Patches for the flaw have been pushed to all Remote Support SaaS customers as of October 9, 2026. Self-hosted customers of Remote Support running versions from 24.3.1 through 26.2.3 are advised to manually update to BT26-0...

A suspected advanced threat actor has been observed exploiting a security flaw in Fortinet FortiOS to deliver a previously unreported memory-resident ARM64 malware known as PEERSTITCH . The attack involves the exploitation of CVE-2025-61624 (CVSS score: 5.4), a path traversal flaw in the command line interpreter of FortiOS, FortiPAM, FortiProxy, and FortiSwitchManager that could allow a privileged attacker to achieve arbitrary write or delete files via specifically crafted arguments to existing commands. It was patched by Fortinet in April 2026. "PEERSTITCH leaves no persistent binary on disk, opens no listening ports and initiates no outbound network connections," Palo Alto Networks Unit 42 researchers Daniel Gott and Shawn Westfall said . "Instead, it communicates through traffic generated by legitimate processes on the infected host, which makes the malware resistant to conventional endpoint and network detection." The cybersecurity company said it discov...

A newly disclosed critical flaw in the Linux kernel allows code inside a virtual machine to read memory on the host computer it runs on. A researcher demonstrated the leak against Vercel's live cloud sandboxes, and Vercel confirmed it. The flaw, now tracked as CVE-2026-99999 and nicknamed PwnEscape , is in the Linux kernel's networking code, not in any one cloud's setup, so it reaches the shared layer that cloud providers use to keep customers' workloads apart. It was found in a Vercel security challenge and reported privately before any public release, and there is no sign it has been used in a real attack. What the Researcher Showed Paulos Yibelo of the security firm pwn.ai found that specially made network packets sent from inside a virtual machine could do three things, he explained in a  technical write-up : read the host's memory, crash the host, and run code on it. All three come from the same kernel flaw. Vercel said in its  report on the challen...

Someone built a tool to steal data, then decided it should scare the victim for fun. Yes, that’s an actual feature. And somehow, it fits right in with this week's security stories. The rest gets interesting in different ways. A small permission can lead to a big theft. A trusted login can hide the wrong person. Old bugs are finding new victims, familiar tools are being put to strange uses, and some flaws are so simple you wonder how nobody spotted them sooner. There's a lot more hiding in the details, including a few twists you probably wouldn't expect. Here's what made the list this week. The threats change every week. Subscribe, and we’ll alert you when each new ThreatsDay Bulletin is out.

The threat actor known as Silent Lynx has been attributed to a fresh set of attacks targeting government organizations across the Commonwealth of Independent States (CIS). The activity, observed from June 2025 through August 2026, involves four different infection chains that make use of macro-enabled documents, PS2EXE downloaders, GitHub-hosted PowerShell, and crafted WinRAR archives exploiting CVE-2025-8088 . The attacks lead to the deployment of custom reverse shells like FoalShell, Chvost, Laplas, and PickleShell that facilitate interactive remote access to compromised hosts, according to Cisco Talos and Recorded Future Insikt Group, which are tracking the campaign under the monikers UAT-6275 and TAG-193.  "UAT-6275's targeting is concentrated in Central Asia, and the wider CIS region," security researcher Ashley Shen said . "Across the reviewed campaigns, observed victims and lure themes span nine countries: Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenist...

NGINX released versions 1.30.6 and 1.31.7 on October 14 to fix five vulnerabilities, one of them present in every release since May 2005. There are three memory bugs that F5, the company behind NGINX, says could crash a worker process or possibly let an attacker run code, and each requires a specific configuration to exploit. A fourth lets an attacker forge a TLS session that could get past client-certificate checks, though F5 calls the forgery non-deterministic and beyond the attacker's control. The fifth lets an HTTP/3 client slip extra bytes into a request that NGINX passes on to a backend. None of the five was in CISA's Known Exploited Vulnerabilities catalog as of October 15, and neither NGINX nor F5 reports attacks.  NGINX rates all five medium . F5 scores the three memory bugs 9.2, Critical, on CVSS v4.0, the TLS flaw 8.3, and the HTTP/3 flaw 6.9. Which Configurations Are Exposed Every one of the five needs a directive you added: an alias...