Summary
Language Servers for AWS vulnerable to arbitrary file write
Language Servers for AWS (the aws/language-servers project) provides the Language Server Protocol implementations that power AWS developer tooling, including the Amazon Q Developer agentic chat experience, across IDEs such as VS Code, JetBrains, Visual Studio, and Eclipse.
Missing symlink validation in Language Servers for AWS may allow an arbitrary file write outside of the workspace trust boundary. This may occur when a local user opens a workspace containing a maliciously crafted symlink that resolves to a file path outside the workspace trust boundary.
Workarounds
No workarounds are available.
References
If you have any questions or comments about this advisory, AWS Security ask that you contact them via their vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Acknowledgement
AWS Security would like to thank Wiz and Maor Dokhanian for collaborating on this issue through the coordinated vulnerability disclosure process.
Impact
If a user opens a maliciously crafted workspace containing a symlink that resides within the workspace but resolves to a location outside the workspace trust boundary, the agent may follow that symlink and write to the external location without prompting the user for approval. This can result in the modification of files outside the intended workspace boundary.
This issue is triggered when a user opens a workspace, trusts it, and the agent subsequently writes to a path within that workspace.
Impacted versions: Language Servers for AWS version <1.69.0.
CVE-2026-12958 has a CVSS score of 7.8 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.117); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
This issue has been addressed in AWS Language Servers version 1.69.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Frequently Asked Questions
- What is CVE-2026-12958? CVE-2026-12958 is a high-severity security vulnerability in @aws/lsp-codewhisperer (npm), affecting versions < 0.0.117. It is fixed in 0.0.117.
- How severe is CVE-2026-12958? CVE-2026-12958 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of @aws/lsp-codewhisperer are affected by CVE-2026-12958? @aws/lsp-codewhisperer (npm) versions < 0.0.117 is affected.
- Is there a fix for CVE-2026-12958? Yes. CVE-2026-12958 is fixed in 0.0.117. Upgrade to this version or later.
- Is CVE-2026-12958 exploitable, and should I be worried? Whether CVE-2026-12958 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-12958 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-12958? Upgrade
@aws/lsp-codewhispererto 0.0.117 or later.