PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-76956 libexpat project CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-20T05:16:29.610Z and has not been modified since then. The vulnerability affects libexpat versions 2.8.2 and 2.8.3, which are susceptible to hash flooding attacks due to misinterpretation of getentropy's return code, leading to insufficient entropy. This results in a denial of service via crafted XML content. Developers and administrators using these versions should review and apply patches or updates to prevent potential attacks. The official CVE Program record and NIST NVD detail page provide primary evidence for CVE-2026-76956. Affected product deployments should be reviewed for potential exposure. Defenders should verify and apply patches or updates to prevent potential denial of service attacks. The CVE record has not been modified since its publication on 2026-08-20T05:16:29.610Z.

Vendor
libexpat project
Product
libexpat
CVSS
MEDIUM 5.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-20
Original CVE updated
2026-09-03
Advisory published
2026-08-20
Advisory updated
2026-09-03

Who should care

Developers and administrators using libexpat versions 2.8.2 and 2.8.3 should review and apply patches or updates to prevent potential denial of service attacks. They should also implement compensating controls to detect and prevent crafted XML content, and monitor systems for potential denial of service attacks. Additionally, security teams and vulnerability management teams should be aware of the potential exposure and take necessary actions to mitigate the vulnerability.

Technical summary

libexpat 2.8.2 and 2.8.3 are vulnerable to hash flooding attacks due to misinterpretation of getentropy's return code, leading to insufficient entropy. This results in a denial of service via crafted XML content. The vulnerability affects developers and administrators using these versions, who should review and apply patches or updates to prevent potential attacks.

Defensive priority

Medium-priority defensive review recommended due to potential denial of service via crafted XML content.

Recommended defensive actions

  • Review and apply patches or updates for libexpat to version 2.8.4 or later.
  • Implement compensating controls to detect and prevent crafted XML content.
  • Monitor systems for potential denial of service attacks.

Evidence notes

Official CVE Program record and NIST NVD detail page provide primary evidence for CVE-2026-76956. Source references from [email protected] offer additional context. The CVE record was published on 2026-08-20T05:16:29.610Z and has not been modified since then. Affected product deployments should be reviewed for potential exposure. Defenders should verify and apply patches or updates to prevent potential denial of service attacks.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-76956 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-76956

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-76956 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-76956

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental 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.