CVE-2026-100310 GNU CVE debrief

Who should care

Defenders responsible for GNU libextractor installations, particularly those using setuid or setgid programs, should assess exposure and prioritize updates to version 1.16 or later.

Why it matters

Defenders should prioritize verifying and updating GNU libextractor installations to version 1.16 or later due to a privilege escalation vulnerability via LIBEXTRACTOR_PREFIX.

• Potential for local privilege escalation
• Execution of arbitrary code with elevated privileges
• Compromise of setuid or setgid programs

Technical summary

The vulnerability in GNU libextractor before version 1.16 allows a local attacker to execute arbitrary code with elevated privileges by setting the LIBEXTRACTOR_PREFIX environment variable to a directory containing a malicious plugin. This occurs because the plugin loading mechanism does not perform proper privilege checks on the search path specified by LIBEXTRACTOR_PREFIX. A local attacker can exploit this by setting LIBEXTRACTOR_PREFIX to a directory containing a malicious plugin that executes arbitrary code with elevated privileges when loaded by a setuid or setgid program. Defenders should prioritize verifying and updating GNU libextractor installations to version 1.16 or later.

Defensive priority

Defenders should prioritize verifying and updating GNU libextractor installations to version 1.16 or later, and restrict write access to the LIBEXTRACTOR_PREFIX environment variable.

Recommended defensive actions

• Verify GNU libextractor installations and update to version 1.16 or later
• Restrict write access to the LIBEXTRACTOR_PREFIX environment variable
• Monitor LIBEXTRACTOR_PREFIX usage and plugin loading
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in GNU libextractor before version 1.16. The vulnerability allows a local attacker to execute arbitrary code with elevated privileges by exploiting the untrusted search path for plugins specified by the LIBEXTRACTOR_PREFIX environment variable.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.