CVE-2026-20896: Gitea Docker image versions up to and including 1.26.2 use REVERSE_PROXY_TRUSTED_PROXIES=* by default, allowin

Q: How do I fix CVE-2026-20896?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Q: Is CVE-2026-20896 being exploited?

CVE-2026-20896 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-20896 affect?

CVE-2026-20896 affects affected software. Severity is critical (CVSS 9.8). 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.

Q: How urgent is CVE-2026-20896?

Priority 74/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-20896 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.8% (top 14%)
CISA exploited list	No
Weakness	CWE-284
Published	2026-07-03
Last modified	2026-10-25

Publisher (CNA): Gitea Limited

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-03 21:16 UTCPublished CVE record published
2026-10-25 15:10 UTCUpdated Record last modified

Exact fixes by distribution

Go · code.gitea.io/gitea · FIXED · 1.26.3 · vulnerable: < 1.26.3 · source

go get code.gitea.io/gitea@v1.26.3 go list -m code.gitea.io/gitea

Fedora ELN · nginx-mod-headers-more · FIXED · 0.41-1.eln159 · FEDORA-2026-31f55f396a · source

sudo dnf upgrade --advisory=FEDORA-2026-31f55f396a

Fedora 46 · erlang-hex_core · FIXED · 0.21.1-1.fc46 · FEDORA-2026-f3389199ff · source

sudo dnf upgrade --advisory=FEDORA-2026-f3389199ff

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Nuclei scan template: Gitea Docker Image <= 1.26.2 - Reverse Proxy Header Authentication Bypass
GitHub PoC: szybnev/cve-2026-20896-gitea-poc (10 stars)
GitHub PoC: rz1027/CVE-2026-20896 (6 stars)
GitHub PoC: XaocZenon/CVE-2026-20896 (6 stars)
Write-up: github.com/go-gitea/gitea/security/advisories/GHSA-f75j-4cw6-rmx4

Advisories and coverage

Official advisories

Canadian Cyber Centre: Gitea security advisory (AV26-845) - Update 1 2026-10-20

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-2026-20896?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-20896 being exploited?

CVE-2026-20896 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-2026-20896 affect?

CVE-2026-20896 affects affected software. Severity is critical (CVSS 9.8). 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.

How urgent is CVE-2026-20896?

Priority 74/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Docker vulnerabilities · Gitea vulnerabilities

References

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