CVE-2026-56131: CWE-416 Use After Free in libexpat project libexpat
CVE-2026-56131 is a use-after-free vulnerability in libexpat before version 2.8.2. The issue arises because the library lacks proper handler call depth tracking when XML_ResumeParser is called from within handlers during policy violations. This can lead to memory corruption and potential instability. The vulnerability has a medium severity rating with a CVSS score of 4.9.
AI Analysis
Technical Summary
The libexpat XML parsing library versions prior to 2.8.2 do not track the depth of handler calls correctly when XML_ResumeParser is invoked from within handlers in cases of policy violations. This flaw can cause a use-after-free condition, similar to the previously known CVE-2026-50219. The vulnerability may result in memory corruption affecting confidentiality, integrity, and availability to a limited extent.
Potential Impact
Successful exploitation of this vulnerability could lead to a use-after-free condition, potentially causing application crashes or memory corruption. The CVSS score indicates limited impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
No official patch or remediation level has been published yet. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should consider avoiding untrusted input that triggers policy violations or calling XML_ResumeParser within handlers. Monitor vendor communications for updates.
CVE-2026-56131: CWE-416 Use After Free in libexpat project libexpat
Description
CVE-2026-56131 is a use-after-free vulnerability in libexpat before version 2.8.2. The issue arises because the library lacks proper handler call depth tracking when XML_ResumeParser is called from within handlers during policy violations. This can lead to memory corruption and potential instability. The vulnerability has a medium severity rating with a CVSS score of 4.9.
CVSS v3.1
Score 4.9medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The libexpat XML parsing library versions prior to 2.8.2 do not track the depth of handler calls correctly when XML_ResumeParser is invoked from within handlers in cases of policy violations. This flaw can cause a use-after-free condition, similar to the previously known CVE-2026-50219. The vulnerability may result in memory corruption affecting confidentiality, integrity, and availability to a limited extent.
Potential Impact
Successful exploitation of this vulnerability could lead to a use-after-free condition, potentially causing application crashes or memory corruption. The CVSS score indicates limited impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
No official patch or remediation level has been published yet. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should consider avoiding untrusted input that triggers policy violations or calling XML_ResumeParser within handlers. Monitor vendor communications for updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-06-19T02:56:35.597Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a34c723f198dc38c1785b25
Added to database: 6/19/2026, 4:35:47 AM
Last enriched: 6/19/2026, 4:50:00 AM
Last updated: 6/19/2026, 5:51:52 AM
Views: 4
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