AWS Systems Manager Agent Flaw Allows Bypass of Port Forwarding Restrictions
Amazon has patched a vulnerability in the AWS Systems Manager agent that allows an authenticated attacker to bypass port forwarding restrictions. The flaw, identified as CVE-2026-89049, was disclosed in a GitHub advisory and affects the agent's handling of blocked addresses.
The agent maintains a blocklist of link-local addresses to prevent forwarding sessions from reaching internal instance services. However, the protection fails to validate equivalent representations of the same address, enabling an attacker to reach the EC2 instance metadata service at 169.254.169.254 by using an alternative notation.
Once access is gained, the attacker can retrieve temporary credentials associated with the instance's IAM role. These credentials can then be used to make API calls to AWS from outside the compromised machine, with permissions defined by the assigned role.
Versions of the agent prior to 3.3.4851.0 are affected. The fix is included in version 3.3.4851.0 and all later releases. AWS advises reviewing any custom builds derived from the agent and restricting access to the AWS-StartPortForwardingSessionToRemoteHost document used to initiate forwarding sessions.
Additional recommendations include auditing Session Manager activity for signs of misuse and reviewing IAM roles attached to instances to enforce the principle of least privilege.
Related articles
Security Week 2644: Active Exploitation of PHP2Shell Vulnerabilities Confirmed
PHP developers released patches for two critical vulnerabilities collectively known as PHP2Shell on October 20, affecting PHP 8.2 through 8.5 as well as older branches. The flaws allow unauthenticated remote code execution on affected servers, which power approximately 70 percent of websites. Despite expectations of immediate exploitation, confirmed attacks with working exploits only began on October 25. CrowdStrike noted technical difficulties in weaponizing the issues in real-world environments. Only one-fifth of top Russian websites had applied the fixes by October 25. Additional incidents included compromised eMudhra certificates, a critical GitLab flaw, and a 16-year-old Broadcom router vulnerability.
Positive Technologies Offers Up to 500,000 Rubles for Bypassing PT Application Firewall
Positive Technologies has expanded its Standoff Bug Bounty program to include rewards for bypassing its web application firewalls. Researchers can earn between 150,000 and 500,000 rubles for demonstrating practical bypasses against PT Application Firewall PRO and PT Application Firewall Cloud. The program targets the core protective mechanisms, including traffic filtering, attack detection rules, and the management layer used by administrators. Submissions must include reproducible attack scenarios that show how malicious requests can pass through undetected, rather than relying on scanner reports or theoretical findings. Reward amounts vary by severity and confirmed business impact, with critical issues in the PRO version paying up to 500,000 rubles. The company plans to use validated findings to strengthen detection rules and improve overall product resilience.
Tailscale SSH Vulnerability Allows Root Access via Unix Socket Redirection
A researcher identified flaws in Tailscale that let an attacker with existing SSH access on one node escalate to root privileges and move laterally across the network. Erica Windisch of Cyberdione Labs demonstrated the issues in lab conditions against Tailscale 1.104.2 and Headscale 0.29.5. The core problem stems from privileged operations performed by the tailscaled process when handling Unix socket redirection, granting an ordinary SSH session access to root-only resources. The researcher used the technique to interact with Docker and run elevated commands, and showed that broad access policies allow automated lateral movement in under a second. Additional issues include denial-of-service conditions and bypasses of certain restrictions. Recommendations include reviewing SSH policies and disabling unnecessary socket redirection, noting that Headscale 0.29.5 lacks an independent way to turn the feature off.
Critical CVE-2026-111497 Out-of-Bounds Write Flaw in Google Brotli Decoder Impacts Broad Range of Environments
A severe vulnerability has been identified in the Google-developed Brotli decoder used for decompressing data in web communications and other applications. The flaw, tracked as CVE-2026-111497, allows out-of-bounds writes when processing specially crafted compressed data, potentially enabling arbitrary code execution, information disclosure, or denial of service. It carries a CVSS v4.0 base score of 9.2 and is rated Critical. Google has released patched versions 1.2.1, 1.1.1, and 1.0.10 of the library. Node.js incorporated the fix in its updates, while Microsoft issued an out-of-band patch for .NET on October 25, 2026, to address the issue. The vulnerability affects any environment relying on the Brotli C implementation for data decompression.