Vulnerability · Published Aug 20, 2026 · Assigned by mitre
CVE-2026-76956
Medium 5.9
In plain English
A medium-severity security flaw in libexpat from libexpat project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.3%top 78.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.21 | expat | 2.8.4-r0 | ALPINE-CVE-2026-76956 |
| Alpine:v3.22 | expat | 2.8.4-r0 | ALPINE-CVE-2026-76956 |
| Alpine:v3.23 | expat | 2.8.4-r0 | ALPINE-CVE-2026-76956 |
| Alpine:v3.24 | expat | 2.8.4-r0 | ALPINE-CVE-2026-76956 |
| Debian:13 | expat | 2.9.0-1~deb13u1 | DEBIAN-CVE-2026-76956 |
| Debian:14 | expat | 2.8.4-1 | DEBIAN-CVE-2026-76956 |
| Ubuntu:22.04:LTS | cadaver | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:24.04:LTS | cadaver | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.04:LTS | cadaver | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | cadaver | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:22.04:LTS | insighttoolkit4 | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:22.04:LTS | matanza | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:24.04:LTS | matanza | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.04:LTS | matanza | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | matanza | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | swish-e | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:22.04:LTS | tdom | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:24.04:LTS | tdom | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.04:LTS | tdom | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | tdom | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:22.04:LTS | wbxml2 | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:24.04:LTS | wbxml2 | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.04:LTS | wbxml2 | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | wbxml2 | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.04:LTS | xmlrpc-c | no fix listed | UBUNTU-CVE-2026-76956 |
| Ubuntu:26.10 | xmlrpc-c | no fix listed | UBUNTU-CVE-2026-76956 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| libexpat project | libexpat | 2.8.2 – before 2.8.4 |
Weakness: CWE-394 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H