GHSA-3pww-vcvm-3gmj CVE-2026-27761 GO-2026-6031

Gitea: API access token scope enforcement bypass on repository RSS/Atom feed endpoints leaks private repository commit data

Medium Go

Severity: 4.3 / 10; Medium · CVSS 3.1
Exploit chance (EPSS): 0.45%; Chance of exploitation in the next 30 days. Higher than 39.23% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-863 Incorrect Authorization
Fix: 1.26.3; Upgrade code.gitea.io/gitea to this version or later

Description

Summary

A Gitea personal access token (PAT) restricted to a non-repository scope (e.g. read:issue) can read the commit history of any private repository the token owner can access, via the repository RSS/Atom feed endpoints. The same token is correctly denied (403) on /raw, /media, /archive, and the contents API. It leaks commit SHAs, full commit messages (which frequently contain secrets and internal context), and committer name + email.

Details

Gitea enforces PAT scope on repository-content endpoints via checkDownloadTokenScope() (added in PR #37698, extended to the archive endpoint by the CVE-2026-20706 fix in 1.26.2). The RSS/Atom feed handlers were never included: they (a) opt into PAT auth via webAuth.AllowBasic, (b) serve private-repo content, but (c) never call checkDownloadTokenScope().

Affected handlers (all carry AllowBasic, none call the scope check):

RenderBranchFeedRSS/Atom - routers/web/feed/render.go (last 10 commits: SHA, title, full message, committer name + email)
ShowFileFeed - routers/web/feed/file.go (per-file commit history)
repo activity feed /{owner}/{repo}.rss / .atom
TagsListFeedRSS/Atom, ReleasesFeedRSS/Atom - routers/web/repo/release.go

Root cause: routers/web/web.go registers the feed routes with webAuth.AllowBasic so a PAT authenticates, but the unit-permission middleware only checks the user's access, not the token's scope. checkDownloadTokenScope (routers/web/repo/download.go and the archive Download in repo.go) exists to close exactly that gap and is absent from the feed handlers. Same class as the recently fixed download/archive bypasses (GHSA-cr4g-f395-h25h / CVE-2026-20706); the feeds are the surface those fixes missed.

PoC

Tested on gitea/gitea:1.26.2-rootless, confirmed present at main HEAD (9608cc2, 2026-06-13).

User carol owns private repo carol/priv with a commit (message: "add confidential secret").
Create a PAT scoped to issues only, no repository scope: curl -u carol:PASS -X POST $HOST/api/v1/users/carol/tokens -d '{"name":"t","scopes":["read:issue"]}'
Scope-enforcing sibling correctly denies it: curl -u carol:$TOK $HOST/carol/priv/raw/branch/main/secret.txt -> 403
The feed leaks private data with the same token: curl -u carol:$TOK $HOST/carol/priv/rss/branch/main -> 200, returns <description>add confidential secret ... this commit message itself is sensitive</description>

Auth (same read:issue token)	/raw/branch/main/secret.txt	/rss/branch/main
anonymous	-	404 (private repo hidden)
invalid token	-	401
read:issue token (no repo scope)	403 (scope enforced)	200 + private commit data
full-scope token	200	200 (legitimate)

Impact

PATs are routinely issued narrowly and handed to third-party bots, CI jobs, or chat integrations that are meant to have no code access. This bypass lets such a token exfiltrate private-repository commit history (messages often hold secrets, ticket refs, internal context) and committer emails for every repository the owner can read. Confidentiality only; no integrity or availability impact. Preconditions: a valid PAT of any non-repository scope owned by a user with read access to the target private repo, and feeds enabled (Other.EnableFeed, default ON).

Suggested fix: call checkDownloadTokenScope(ctx) at the start of each feed handler (mirroring download.go). Longer-term, enforce repository token scope in a single route-group middleware wherever AllowBasic / AllowOAuth2 is set on a repo-content route, so the next added endpoint cannot miss it.

Affected versions

Go

Package	Vulnerable	Fixed in
code.gitea.io/gitea	`< 1.26.3`	`1.26.3`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

code.gitea.io/gitea Go → `1.26.3`

go

go get code.gitea.io/gitea@v1.26.3 && go mod tidy

Severity breakdown

CVSS 3.1 4.3

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Weakness

CWE-863: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

How to prevent it

Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-27761

Packages

github.com/go-gitea/gitea

Timeline

Jul 3, 2026 Published
Oct 25, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-rcr6-4jqh-j84m Gitea: Remote Code Execution via diffpatch Git Hook Installation	Critical Known exploited	Also affects code.gitea.io/gitea
GHSA-fq2p-5p22-8g6j Gitea: Public-Only Personal access tokens scope bypass in Organization and Permission Endpoints	Medium	Also affects code.gitea.io/gitea
GHSA-2wm4-vwp6-v7xc Gitea: SSRF via Migration Asset Downloads Bypasses hostmatcher — Reads Internal Files and Cloud Metadata	High	Also affects code.gitea.io/gitea
GHSA-3r5c-2xxx-h872 Gitea: Webhook Authorization Header Returned in Plaintext via API	Low	Also affects code.gitea.io/gitea
GHSA-frpw-3h2q-4jj6 Gitea: Cross-Repo Information Disclosure via Org-Level Actions Run/Job APIs	Medium	Also affects code.gitea.io/gitea
GHSA-q423-49rw-g9mh Gitea: GHSA-8fwc-qjw5-rvgp ClearRepoWatches fix not applied to API EditRepo path — sister code path retains stale watches on public->private	Medium	Also affects code.gitea.io/gitea
GHSA-2fcr-jfvc-vgg2 Gitea: Two SSRF findings	High	Also affects code.gitea.io/gitea
GHSA-fw57-jgch-pgf3 Gitea: ParseAcceptLanguage quadratic-time DoS via Locale middleware on unauthenticated requests	High	Also affects code.gitea.io/gitea

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