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Fencer Vulns
critical 9.8

CVE-2020-29007 json

The Score extension through 0.3.0 for MediaWiki has a remote code execution vulnerability due to improper sandboxing of the GNU LilyPond ex…

published 2023-04-15 3 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21389

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

The Score extension through 0.3.0 for MediaWiki has a remote code execution vulnerability due to improper sandboxing of the GNU LilyPond executable. This allows any user with an ability to edit articles (potentially including unauthenticated anonymous users) to execute arbitrary Scheme or shell code by using crafted {{Image data to generate musical scores containing malicious code.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
21 mo ago

Exploit prediction

2.34% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/seqred-s-a/cve-2020-29007 referenced PoC, tagged "exploit" by a source, unverified
  • phabricator.wikimedia.org https://phabricator.wikimedia.org/T257062 referenced PoC, tagged "exploit" by a source, unverified
  • seqred.pl https://seqred.pl/en/cve-2020-29007-remote-code-execution-in-mediawiki-score/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.