CVE-2026-92391 curl CVE debrief

Who should care

Defenders responsible for systems using libcurl should assess exposure and prioritize verification of affected versions and remediation to prevent potential crashes due to stack overflow during libcurl cleanup operations.

Why it matters

A stack overflow vulnerability in libcurl's `curl_mime_free` function can cause a host process crash during cleanup operations, requiring defenders to assess exposure and prioritize remediation.

• Potential crashes or errors related to libcurl cleanup operations
• Need to verify affected versions and apply patches or mitigations
• Prioritize remediation for systems using libcurl

Technical summary

A deeply nested multipart MIME structure constructed via the public API causes a stack overflow in libcurl during normal cleanup operations. An excessive recursion depth within `curl_mime_free` leads to unbounded stack frame allocation during structure traversal, ultimately crashing the host process. This vulnerability affects systems using libcurl, particularly those with user-inputted or untrusted MIME data. Defenders should prioritize verifying affected versions and applying patches or mitigations to prevent potential crashes due to stack overflow during libcurl cleanup operations.

Defensive priority

Defenders should prioritize verifying affected versions and applying patches or mitigations to prevent potential crashes due to stack overflow during libcurl cleanup operations.

Recommended defensive actions

• Verify affected versions of libcurl and apply patches or mitigations
• Assess exposure and prioritize remediation for systems using libcurl
• Monitor for potential crashes or errors related to libcurl cleanup operations
• 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 source item provide details on the stack overflow vulnerability in libcurl. Defenders should verify affected versions, assess exposure, and prioritize remediation. Evidence from the CVE Program and NVD detail page supports this assessment. However, specific version information and additional context on exploitation are limited. Further verification tasks are necessary to confirm affected scope and severity.

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.