CVE-2026-116878: Semantic MediaWiki from 2.5.0 before 7.3.1 contains an uncontrolled resource consumption vulnerability that al

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HIGH 7.5REMOTEUPGRADE

CVE-2026-116878 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 from 2.5.0 before 7.3.1 contains an uncontrolled resource consumption vulnerability that allows anonymous attackers to force quadratic computation by supplying a zero limit to Special:PropertyLabelSimilarity. Attackers can send repeated requests with limit=0 to bypass the SQL LIMIT and trigger pairwise similar_text() comparisons, exhausting PHP CPU, memory, and database connections.

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 70%)
CISA exploited list	No
Weakness	CWE-400
Published	2026-10-27
Last modified	2026-11-04

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

Last updated 2026-11-04 · 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
2026-11-04 16:56 UTCUpdated Record last modified

semantic-mediawiki semantic mediawiki UPGRADE

Affected: >= 2.5.0 and < 7.3.1

Fixed in: 7.3.1

Safe to downgrade to: a release before 2.5.0

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 2.5.0 (Debian / Ubuntu)

apt-cache madison semantic-mediawiki sudo apt install semantic-mediawiki=<VERSION_BEFORE_2.5.0> 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_2.5.0> 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-2026-116878 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-2026-116878?

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

Is CVE-2026-116878 being exploited?

CVE-2026-116878 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-2026-116878 affect?

CVE-2026-116878 affects semantic mediawiki. Severity is high (CVSS 7.5). Semantic MediaWiki from 2.5.0 before 7.3.1 contains an uncontrolled resource consumption vulnerability that allows anonymous attackers to force quadratic computation by supplying a zero limit to Special:PropertyLabelSimilarity. Attackers ca

How urgent is CVE-2026-116878?

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

Software pages

PHP vulnerabilities

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References

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