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Fencer Vulns
high 7.3

CVE-2021-39887 json

A stored Cross-Site Scripting vulnerability in the GitLab Flavored Markdown in GitLab CE/EE version 8.4 and above allowed an attacker to ex…

published 2021-10-05 5 y ago modified 2026-09-10 1 mo ago also BIT-gitlab-2021-39887 , EUVD-2021-26243

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

A stored Cross-Site Scripting vulnerability in the GitLab Flavored Markdown in GitLab CE/EE version 8.4 and above allowed an attacker to execute arbitrary JavaScript code on the victim's behalf.

Patch / fix

  • bitnami gitlab 14.1.7, 14.2.5, 14.3.1
  • gitlab gitlab 14.1.7, 14.2.5, 14.3.1
  • gitlab gitlab_enterprise 14.1.7, 14.2.5, 14.3.1
  • gitlab Arch Linux 14.3.1-1

arch linux advisories AVG-2431

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
OSV 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
bitnami gitlab
>=8.4.0, <14.1.7
>=14.2.0, <14.2.5
>=14.3.0, <14.3.1
14.1.7
14.2.5
14.3.1

Affected products

  • GitLab GitLab

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
Technology feeds

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Enhance with deb and rpm package type records.