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CVE-2026-20896— Gitea Docker image trusts spoofable reverse-proxy headers by default

Quick assessment

Affected
Gitea Gitea Open Source Git Server
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Gitea是Gitea组织开源的一个基于Go开发的轻量型git服务。 Gitea 1.26.2及之前版本存在权限许可和访问控制问题漏洞，该漏洞源于默认使用REVERSE_PROXY_TRUSTED_PROXIES=*，当启用反向代理认证标头（如X-WEBAUTH-USER）时，允许任意源IP冒充用户。

CVSS 9.8 · Critical EPSS 2.76% · P86

Public Exploits 1

Nuclei · 1 CVE-2026-20896.yaml [template]

Affected Version Matrix 1

VendorProduct Version RangeStatus
Gitea Gitea Open Source Git Server ≤ 1.26.2 affected
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I. Basic Information for CVE-2026-20896

Vulnerability Information
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Vulnerability Title
Gitea Docker image trusts spoofable reverse-proxy headers by default
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
访问控制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Gitea 权限许可和访问控制问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Gitea是Gitea组织开源的一个基于Go开发的轻量型git服务。 Gitea 1.26.2及之前版本存在权限许可和访问控制问题漏洞，该漏洞源于默认使用REVERSE_PROXY_TRUSTED_PROXIES=*，当启用反向代理认证标头（如X-WEBAUTH-USER）时，允许任意源IP冒充用户。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Gitea Gitea Open Source Git Server 0 ~ 1.26.2 -

II. Public POCs for CVE-2026-20896

# POC Description Source Link Shenlong Link
1 The official Gitea Docker image through version 1.26.2 ships with REVERSE_PROXY_TRUSTED_PROXIES set to a wildcard, causing Gitea to trust reverse-proxy authentication headers (X-WEBAUTH-USER) from any source IP instead of restricting trust to the configured reverse proxy. When reverse-proxy authentication is enabled, an unauthenticated remote attacker can impersonate any existing user, including an administrator, by sending the target username in the X-WEBAUTH-USER header. https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-20896.yaml POC Details
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III. Intelligence Information for CVE-2026-20896

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Patches & Fixes for CVE-2026-20896 (1)

Vendor Advisories for CVE-2026-20896 (1)

Security Blog Posts for CVE-2026-20896 (1)

Vendor Pages for CVE-2026-20896 (1)

Same Patch Batch · Gitea · 2026-07-03 · 40 CVEs total

CVE-2026-58426 9.6 CRITICAL Gitea Actions Artifacts V4 signed URL HMAC ambiguity allows cross-repository artifact read
CVE-2026-22874 9.6 CRITICAL Gitea webhook and migration allow-list filtering permits SSRF
CVE-2026-58424 8.9 HIGH Permanent Fork PR Workflow Approval Gate Bypass
CVE-2026-28737 8.7 HIGH Gitea 3D file viewer allows stored XSS through glTF extensionsRequired
CVE-2026-26231 8.5 HIGH Gitea maintainer-edit permissions allow unauthorized commits to readable repositories
CVE-2026-28699 8.1 HIGH Gitea Basic Auth bypasses OAuth2 access token scopes
CVE-2026-28744 8.1 HIGH Gitea Git smart HTTP bypasses repository token scopes for bearer tokens
CVE-2026-22555 8.1 HIGH Gitea organization forks can expose organization secrets without create permission
CVE-2026-58423 7.7 HIGH LFS authentication bypass via malformed SSH sub-verb allows unauthorized read access to pr
CVE-2026-28740 7.1 HIGH Gitea LFS object reuse bypasses Code-unit authorization
CVE-2026-20779 7.1 HIGH Gitea TOTP single-use enforcement defect allows OTP replay
CVE-2026-58418 6.5 MEDIUM SSRF via HTTP Redirect in Repository Migration
CVE-2026-27783 4.3 MEDIUM Gitea issue-template APIs bypass repository unit authorization
CVE-2026-27761 4.3 MEDIUM Gitea repository feeds bypass API token scope enforcement
CVE-2026-25714 4.3 MEDIUM Gitea user organization API bypasses public-only token filtering
CVE-2026-20706 Gitea repository archive downloads bypass token scope checks
CVE-2026-20909 Gitea tracked-time list endpoint has insufficient permission checks
CVE-2026-58421 Unauthenticated ReDoS via CODEOWNERS pattern matching allows denial of service
CVE-2026-58419 Notification API leaks private issue metadata after access revocation
CVE-2026-28705 Gitea repository dumps write release assets using unsafe path names

Showing top 20 of 40 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Gitea Open Source Git Server
Same vendor: Gitea
Same weakness: CWE-284

V. Comments for CVE-2026-20896

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