CVE-2026-20706: Gitea Auth Bypass Vulnerability

CVE-2026-20706 Overview

CVE-2026-20706 is an access control weakness in Gitea, the self-hosted Git service written in Go. Gitea versions up to and including 1.26.1 allow repository archive downloads to bypass token scope checks on the web archive download endpoint. An attacker with a token that lacks the required scope can still retrieve full repository archives, exposing source code and repository history over the network. The issue is tracked as CWE-284: Improper Access Control and was fixed in Gitea 1.26.2.

Critical Impact
Attackers holding a scoped or otherwise limited API token can download complete repository archives from private repositories, defeating the token permission model and leaking source code.

Affected Products

Gitea 1.26.1 and all earlier versions in the 1.26.x branch
Gitea self-hosted deployments exposing the web archive download endpoint
Instances relying on token scopes to restrict repository read access

Discovery Timeline

2026-07-03 - CVE-2026-20706 published to NVD
2026-07-06 - Last updated in NVD database
Patch release - Gitea 1.26.2 published with the fix, documented in the Gitea 1.26.2 release notes and GitHub release v1.26.2
Advisory - Coordinated through GitHub Security Advisory GHSA-cr4g-f395-h25h

Technical Details for CVE-2026-20706

Vulnerability Analysis

Gitea issues API tokens that carry a set of scopes controlling which endpoints and repository operations the token can invoke. The web archive download endpoint serves compressed archives (zip, tar.gz, bundle) built from repository refs. In vulnerable releases, this endpoint does not evaluate the presenter's token scope against the required repository read permission. A token that would be rejected at the standard REST API layer is accepted when the same identity requests an archive via the web download path. The result is unauthorized retrieval of repository contents, including branches, tags, and historical commits reachable from those refs.

The pull request that introduces the fix adds the missing scope enforcement so the archive handler shares the same authorization logic used by other repository read endpoints.

Root Cause

The root cause is missing scope validation on the archive download handler. The endpoint verified identity but did not confirm that the presented token carried a scope permitting repository read. This is a classic improper access control failure [CWE-284] where a single code path bypassed the platform's token permission model.

Attack Vector

Exploitation is performed over the network with no user interaction. An attacker who has obtained any valid API token, including a token minted for an unrelated, narrowly scoped purpose, sends an HTTP GET request to the archive endpoint for a target repository and branch. The server returns the archive without validating that the token scope authorizes repository read. Tokens leaked from CI pipelines, misconfigured integrations, or over-privileged service accounts become sufficient to exfiltrate source code that the token was never intended to access.

No verified public exploit code is currently available. Technical detail is provided in the Gitea security advisory.

Detection Methods for CVE-2026-20706

Indicators of Compromise

Unexpected GET requests to paths matching /{owner}/{repo}/archive/*.zip, *.tar.gz, or *.bundle originating from tokens that do not otherwise access the repository.
Archive downloads from API tokens whose recorded scopes do not include repository read for the target owner or repository.
High-volume archive requests from a single token or IP addressing multiple private repositories in a short window.

Detection Strategies

Correlate Gitea access logs with the token identifier and issued scope catalog to flag archive downloads by tokens lacking read:repository or equivalent scope.
Alert on archive downloads targeting private repositories where the requesting principal has no history of API interaction with that repository.
Baseline normal archive download volume per token and trigger on statistical anomalies.

Monitoring Recommendations

Forward Gitea application and reverse proxy logs to a central analytics platform and retain request URL, token ID, response size, and status code.
Enable audit logging for token issuance, scope changes, and archive endpoint access.
Monitor egress bandwidth from the Gitea host for unusual archive-sized transfers to external destinations.

How to Mitigate CVE-2026-20706

Immediate Actions Required

Upgrade all Gitea instances to version 1.26.2 or later without delay.
Rotate API tokens that may have been exposed, especially tokens issued to CI systems, bots, or third-party integrations.
Review audit logs for archive endpoint access since the earliest deployment of an affected 1.26.x release and identify unauthorized downloads.

Patch Information

The fix is included in Gitea 1.26.2. See the release announcement, the tagged release on GitHub, and the corresponding pull request for change details. Administrators running container images should pull the 1.26.2 tag and redeploy. Package-based deployments should apply the vendor-provided update for their distribution.

Workarounds

Restrict network access to the Gitea archive endpoint using a reverse proxy or web application firewall until the upgrade is applied.
Revoke any API tokens that are not strictly required and reissue with minimum necessary scope after patching.
Enforce authentication proxies or IP allow-listing in front of Gitea to limit exposure of the archive path to trusted networks.

bash

# Example: block anonymous and non-allowlisted access to archive endpoints at the reverse proxy
# NGINX snippet - apply until Gitea is upgraded to 1.26.2
location ~ ^/[^/]+/[^/]+/archive/ {
    allow 10.0.0.0/8;
    deny  all;
    proxy_pass http://gitea_upstream;
}