Skip to content
Fencer Vulns
critical 9.8

CVE-2026-20896 json

Gitea Docker image trusts spoofable reverse-proxy headers by default

published 2026-07-03 4 mo ago modified 2026-10-25 14 d ago also GHSA-f75j-4cw6-rmx4 , GO-2026-6051 , EUVD-2026-41614

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known, plus a Nuclei check

Summary

Gitea Docker image versions up to and including 1.26.2 use REVERSE_PROXY_TRUSTED_PROXIES=* by default, allowing any source IP to impersonate a user when reverse-proxy authentication headers such as X-WEBAUTH-USER are enabled.

Patch / fix

  • go code.gitea.io/gitea 1.26.3
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

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

Exploit prediction

2.76% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Gitea Docker Image <= 1.26.2 - Reverse Proxy Header Authentication Bypass nuclei detection template
  • github.com https://github.com/go-gitea/gitea/security/advisories/GHSA-f75j-4cw6-rmx4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

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

Affected packages

ecosystem package affected fixed in
go code.gitea.io/gitea
<1.26.3
1.26.3

Affected products

  • Gitea Gitea Open Source Git Server

Classification

Weakness

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.