Zero Day | Breaking Cybersecurity News | The Hacker News

The threat actor known as Head Mare has been observed weaponizing security flaws in unpatched TrueConf servers once again in attacks targeting Russian companies spanning instrumentation, electronics, transport, energy, IT, and software development sectors. Russian cybersecurity vendor Kaspersky said it detected the attacks in July 2026. The activity involves exploiting a vulnerability chain in the TrueConf videoconferencing server to replace the original TrueConf client installers with poisoned versions that deliver the PhantomCore backdoor and remote access trojan (RAT) into susceptible systems. The vulnerabilities, tracked as KLCERT-26-057 and KLCERT-26-058, enable arbitrary code execution with elevated privileges. The attack impacts TrueConf server versions 5.3.x up to 5.3.9, 5.4.x up to 5.4.9, 5.5.x up to 5.5.5, and earlier. The attack chain is as follows - Attackers connect to the TrueConf server on TCP port 4307, which is open by default. Upon successful conn...

OpenAI has announced that it's pausing some "internal activities" involving its upcoming artificial intelligence (AI) model Astra after an internal evaluation found it had made significant advancements in agentic coding and cybersecurity. In response to the discovery, the AI upstart said it's implementing security controls for higher-capability models and associated activities, such as isolated testing environments, restricted network and tool access, enhanced model weight protections and encryption, additional monitoring and detection capabilities, and sandboxed execution. "We are pausing internal activities involving Astra that do not yet meet these strengthened security control requirements," it said in a statement. "We have implemented universal monitoring for risky actions and misalignment across all agentic applications of Astra, including training and evaluation. Monitors evaluate the model's Chain of Thought and trigger a security re...

OpenAI on Tuesday revealed the rogue artificial intelligence (AI) agent that escaped its sealed evaluation environment and broke into Hugging Face's production environment also hacked multiple third-party accounts and services as part of the attack. The latest disclosure shows that the security incident, which stemmed from an internal security test, was more extensive in scope than previously thought. The AI company said its ongoing review of the incident revealed a "small number of cases" where the models, including GPT-5.6 Sol and an "even more capable pre-release model," identified and used exposed credentials at the account-level on other publicly-available services. "This includes four accounts on four services as part of the Hugging Face incident (and a few accounts accessed as part of other evaluations)," it said. "One of these four accounts was used as an outbound relay and staging path, and another account was used for data st...

Microsoft has come out strongly in favor of Coordinated Vulnerability Disclosure (CVD), urging the research community to share their findings and give affected vendors an opportunity to better understand the impact and address them before they are publicly disclosed. The development comes after a researcher named Chaotic Eclipse (aka Nightmare-Eclipse) disclosed details of multiple zero-day vulnerabilities affecting various Windows components, including Defender and BitLocker, over the past month, citing a breakdown in Microsoft's handling of the vulnerability disclosure process. "In recent weeks, several zero-day vulnerabilities have been publicly disclosed," the tech giant said . "The details of these vulnerabilities were not shared with Microsoft prior to release, and the disclosures put our customers at unnecessary risk." "In response to the unnecessary risk created by these disclosures, our security teams have been working around the clock to ...