CVE-2026-80489 The GNU C Library CVE debrief

Who should care

Defenders responsible for applications using GNU C Library versions 2.3 to 2.44 should assess exposure and verify output buffer handling. Operators, platform administrators, vulnerability management teams, and security teams should review the vulnerability and take necessary precautions. The vulnerability may lead to denial-of-service attacks if exploited, and defenders should take steps to mitigate the risk.

Why it matters

The vulnerability affects GNU C Library versions 2.3 to 2.44 and may cause applications to hang when converting crafted EUC_JISX0213 input, potentially leading to denial-of-service attacks. Defenders should assess exposure and verify output buffer handling in affected applications.

• Potential denial-of-service attacks through crafted EUC_JISX0213 input
• Verification of output buffer handling in affected applications
• Assessment of exposure in applications using GNU C Library versions 2.3 to 2.44

Technical summary

The GNU C Library converter for EUC_JISX0213 character set may hang when converting crafted input, causing a denial-of-service condition. The vulnerability affects GNU C Library versions 2.3 to 2.44 and is related to EUC_JISX0213 character set conversions. The input must be attacker-controlled and the application must convert it with an output buffer small enough to split the two code points. Defenders should assess exposure and verify output buffer handling in affected applications. The affected character set is not commonly used.

Defensive priority

Assess exposure in applications using GNU C Library versions 2.3 to 2.44 for EUC_JISX0213 character set conversions.

Recommended defensive actions

• Assess applications using GNU C Library versions 2.3 to 2.44 for EUC_JISX0213 character set conversions
• Verify output buffer handling in affected applications
• Monitor for potential denial-of-service attacks
• 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 vulnerability affects GNU C Library versions 2.3 to 2.44 and is related to EUC_JISX0213 character set conversions. The input must be attacker-controlled and the application must convert it with an output buffer small enough to split the two code points. Only the EUC_JISX0213 character set is affected, which is not commonly used. Defenders should verify output buffer handling in affected applications and assess exposure.

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.