CVE-2026-116871: Semantic MediaWiki 3.0.0 before 7.3.1 contains an uncontrolled recursion vulnerability in LegacyParser::getSub

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-116871 is a high-severity flaw (CVSS 7.5) affecting semantic mediawiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Semantic MediaWiki 3.0.0 before 7.3.1 contains an uncontrolled recursion vulnerability in LegacyParser::getSubqueryDescription() that processes nested query tokens before depth limits apply. Unauthenticated attackers can submit deeply nested query elements to the action=ask API to consume substantial CPU and memory, tying up request workers.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-674
Published	2026-10-27
Last modified	2026-11-03

Publisher (CNA): VulnCheck · Vendor: semantic-mediawiki

Last updated 2026-11-03 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-27 11:17 UTCPublished CVE record published
2026-11-03 16:42 UTCUpdated Record last modified

semantic-mediawiki semantic mediawiki UPGRADE

Affected: >= 3.0.0 and < 7.3.1

Fixed in: 7.3.1

Safe to downgrade to: a release before 3.0.0

1. Check installed version

apt-cache policy semantic-mediawiki || rpm -q semantic-mediawiki || semantic-mediawiki --version

2. UPGRADE to 7.3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade semantic-mediawiki

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade semantic-mediawiki

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison semantic-mediawiki sudo apt install semantic-mediawiki=<VERSION_BEFORE_3.0.0> sudo apt-mark hold semantic-mediawiki

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list semantic-mediawiki sudo dnf downgrade semantic-mediawiki-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add semantic-mediawiki

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Advisories and coverage

Research and news

Vulners Bulletins: CVE-2026-116871 2026-10-27

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-116871?

semantic mediawiki: upgrade to 7.3.1. Exact commands for each OS are on this page.

Is CVE-2026-116871 being exploited?

CVE-2026-116871 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-116871 affect?

CVE-2026-116871 affects semantic mediawiki. Severity is high (CVSS 7.5). Semantic MediaWiki 3.0.0 before 7.3.1 contains an uncontrolled recursion vulnerability in LegacyParser::getSubqueryDescription() that processes nested query tokens before depth limits apply. Unauthenticated attackers can submit deeply neste

How urgent is CVE-2026-116871?

Priority 44/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

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References

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