CVE-2026-12957 Amazon Web Services CVE debrief

Who should care

Developers and administrators using Language Servers for AWS before version 1.65.0 should be aware of this vulnerability and take immediate action to upgrade. This vulnerability requires local user interaction and trust in the workspace, making it a significant risk for environments where workspaces are frequently shared or opened. Security teams should prioritize patching and monitoring for potential exploitation attempts.

Technical summary

The vulnerability in Language Servers for AWS before version 1.65.0 is due to improper trust boundary enforcement. When a local user opens a maliciously crafted workspace, any commands within the project configuration files may be automatically executed. This requires the user to trust the workspace when prompted. The CVSS:4.0 vector for this vulnerability is AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. The weakness associated with this vulnerability is CWE-732.

Defensive priority

High priority should be given to upgrading Language Servers for AWS to version 1.65.0 or higher. Security teams should monitor for potential exploitation attempts and ensure that workspaces are validated before being opened.

Recommended defensive actions

• Upgrade Language Servers for AWS to version 1.65.0 or higher.
• Validate workspaces before opening them.
• Monitor for potential exploitation attempts.
• Educate users on the risks of opening untrusted workspaces.
• Implement compensating controls to detect and prevent exploitation.

Evidence notes

The CVE-2026-12957 record was obtained from the official CVE database and the NVD detail page. Additional information was gathered from the Amazon security bulletin and the GitHub advisory. The CVSS score and vector were obtained from the NVD detail page.

Official resources