Vulnerability · Published May 11, 2026 · Assigned by wikimedia-foundation
CVE-2026-34086AbuseFilter misuses ::userCanBitfield, exposing access-controlled information
Low 2.1
In plain English
A low-severity improper input validation in AbuseFilter from Wikimedia Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)2.1Low
Exploit odds (30 days)0.2%top 84.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Vulnerability in Wikimedia Foundation AbuseFilter. This issue affects AbuseFilter: from * before 1.43.7, 1.44.4, 1.45.2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mediawiki | no fix listed | DEBIAN-CVE-2026-34086 |
| Debian:13 | mediawiki | 1:1.43.8+dfsg-1~deb13u1 | DEBIAN-CVE-2026-34086 |
| Debian:14 | mediawiki | 1:1.43.8+dfsg-1 | DEBIAN-CVE-2026-34086 |
| Ubuntu:25.10 | mediawiki | no fix listed | UBUNTU-CVE-2026-34086 |
| Ubuntu:26.04:LTS | mediawiki | no fix listed | UBUNTU-CVE-2026-34086 |
| Ubuntu:26.10 | mediawiki | no fix listed | UBUNTU-CVE-2026-34086 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Wikimedia Foundation | AbuseFilter | * – before 1.43.7, 1.44.4, 1.45.2 |
Weakness: CWE-20 · Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/S:N/AU:Y