CVE-2026-74860 Red Hat CVE debrief

Who should care

Defenders responsible for Python applications using the libxml2 SAX bindings, as well as those managing systems that use libxml2 with Python bindings enabled, should assess exposure and prioritize patching.

Why it matters

Defenders should prioritize verifying and applying patches for libxml2 with Python bindings enabled, assessing exposure in Python applications using the libxml2 SAX bindings, and monitoring for potential DoS attacks.

• Potential denial of service (DoS) due to a reproducible crash in Python applications using the libxml2 SAX bindings
• Need to verify and apply patches for libxml2 with Python bindings enabled
• Need to assess exposure in Python applications using the libxml2 SAX bindings
• Potential for attackers to exploit this vulnerability by providing specially crafted XML documents

Technical summary

The vulnerability is caused by a double-free error in the SAX attributeDecl callback handler, which can be triggered by a specially crafted XML document containing a Document Type Definition (DTD) with enumerated attribute values. This flaw can lead to a denial of service (DoS) due to a reproducible crash in Python applications using the libxml2 SAX bindings. The vulnerability is related to libxml2 with Python bindings enabled. A remote attacker could exploit this vulnerability by providing a specially crafted XML document.

Defensive priority

Defenders should prioritize verifying and applying patches for libxml2 with Python bindings enabled, assessing exposure in Python applications using the libxml2 SAX bindings, and monitoring for potential DoS attacks.

Recommended defensive actions

• Verify and apply patches for libxml2 with Python bindings enabled
• Assess exposure in Python applications using the libxml2 SAX bindings
• Monitor for potential DoS 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 CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and references to affected systems. The vulnerability is related to libxml2 with Python bindings enabled. A remote attacker could exploit this vulnerability by providing a specially crafted XML document containing a Document Type Definition (DTD) with enumerated attribute values. This triggers a double-free error in the SAX attributeDecl callback handler, where a string is freed twice. The lack of detailed information on affected

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.