What is CVE-2026-76956?

CVE-2026-76956 is a medium-severity vulnerability in Libexpat Project, classified under CWE-394. CVSS score: 5.9/10. Published 2026-08-20.

How severe is CVE-2026-76956?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Vulnerability in Libexpat Project

CVE-2026-76956

In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.

Published 2026-08-20 · last modified 2026-09-08.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (19.3th percentile), scored 2026-10-05.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-394

References

github.com/libexpat/libexpat/pull/1326 (Patch, Issue Tracking)
github.com/libexpat/libexpat/pull/1329 (Patch, Issue Tracking)

Frequently asked questions

What is CVE-2026-76956?: CVE-2026-76956 is a medium-severity vulnerability in Libexpat Project, classified under CWE-394. CVSS score: 5.9/10. Published 2026-08-20.
How severe is CVE-2026-76956?: Medium severity. CVSS v3 base score is 5.9 out of 10.