CVE-2026-81687 jahlives CVE debrief

Who should care

Defenders responsible for systems using openssl_encrypt should assess exposure and potential impact of CPU resource consumption. This includes operators, platform administrators, vulnerability management teams, and security teams who need to verify exposure of openssl_encrypt versions before 1.4.9 and evaluate the potential impact on system performance and availability.

Why it matters

Defenders should prioritize verifying exposure of openssl_encrypt versions before 1.4.9 and assessing the impact of potential CPU resource consumption, as attackers can craft files to consume CPU resources for unbounded periods.

• Potential CPU resource consumption leading to denial-of-service
• Need to verify exposure of openssl_encrypt versions before 1.4.9
• Potential impact on system performance and availability

Technical summary

openssl_encrypt versions before 1.4.9 fail to enforce a time ceiling on key derivation function iteration counts specified in file metadata, allowing attackers to craft files with extremely high KDF iteration counts to consume CPU resources for unbounded periods before password verification occurs. This vulnerability can lead to denial-of-service attacks and impact system performance and availability. Defenders should prioritize verifying exposure of openssl_encrypt versions before 1.4.9 and assessing the impact of potential CPU resource consumption.

Defensive priority

Defenders should prioritize verifying exposure of openssl_encrypt versions before 1.4.9 and assessing the impact of potential CPU resource consumption.

Recommended defensive actions

• Verify openssl_encrypt version and assess exposure
• Evaluate potential impact of CPU resource consumption
• Consider upgrading to version 1.4.9 or later
• 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 description notes that openssl_encrypt versions before 1.4.9 fail to enforce a time ceiling on key derivation function iteration counts specified in file metadata, allowing attackers to craft files that consume CPU resources for unbounded periods.

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.