# Gitea: Blind SSRF in OAuth2 avatar synchronization via unvalidated OIDC picture claim

Advisory record · `GHSA-x77v-q46j-393g`

- **Identifiers:** `GHSA-x77v-q46j-393g` · `CVE-2026-23603` · `GO-2026-6083`
- **State:** Confirmed
- **Severity:** CVSS 3.1 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-918](https://cwe.mitre.org/data/definitions/918.html)
- **Tags:** [Server-side request forgery (SSRF)](https://agentprime.io/advisories/tag/ssrf.md)
- **Published:** 21 Jul 2026
- **Updated:** 27 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 21 Jul 2026, 20:22 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `code.gitea.io/gitea` (Go): affected `<1.27.0`; fixed in `1.27.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Gitea versions before 1.27.0 are affected when the OAuth2 client setting UPDATE_AVATAR is enabled. A user who can control the avatar value (commonly the OIDC picture claim) from a configured OAuth2 or OIDC provider can make the Gitea server send outbound GET requests to arbitrary addresses, including internal and cloud metadata endpoints, which is a blind server-side request forgery. Upgrade to Gitea 1.27.0 or later; the source does not describe another workaround.

Written 6 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 3.1 Low, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.0029, the 21st percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:55 UTC: First seen by agentprime
- 31 Oct 2026, 14:55 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-x77v-q46j-393g)

## Sources

- [GitHub Advisory Database: GHSA-x77v-q46j-393g](https://github.com/advisories/GHSA-x77v-q46j-393g)
- [OSV: GHSA-x77v-q46j-393g](https://osv.dev/vulnerability/GHSA-x77v-q46j-393g)
- <https://github.com/go-gitea/gitea/security/advisories/GHSA-x77v-q46j-393g>
- <https://github.com/go-gitea/gitea/pull/38406>
- <https://github.com/go-gitea/gitea/pull/38426>
- <https://github.com/go-gitea/gitea/commit/de4b8277e9cb576f2315fb03b5ab6478b42a1d31>
- <https://github.com/go-gitea/gitea/commit/f69e15afe7496cc62e96dab244629c69eb31a7bf>
- <https://github.com/go-gitea/gitea>
- <https://github.com/go-gitea/gitea/releases/tag/v1.27.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-x77v-q46j-393g>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-x77v-q46j-393g/>. Everything for agents: <https://agentprime.io/llms.txt>.