CVE-2026-90679 Auth bypass in Forgejo
Remote attackers can spoof ActivityPub identities in Forgejo when federation is enabled, bypassing signature verification to attribute actions to arbitrary actors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-90679?
CVE-2026-90679 is a medium-severity authentication bypass vulnerability in Forgejo, published on 13 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Forgejo 13.0.0 through 16.0.4, when "[federation] ENABLED = true" is set, has a spoofing issue that affects identity integrity but does not allow account takeover or content modification. It does not verify that the HTTP Signature on an incoming ActivityPub activity was produced by the key belonging to the actor named in the activity body. The signature verification in routers/api/v1/activitypub/reqsignature.go validates the request signature, but the inbox activity handlers subsequently read the acting identity from the attacker-controlled JSON body without binding it to the verified signing key. Additionally, the signed Digest header is not recomputed against the received request body. A remote attacker who hosts a single valid ActivityPub actor and keypair can therefore submit signature-valid activities attributed to any actor identity they name.
Weakness: CWE-348
Which versions are affected by CVE-2026-90679?
How do I fix CVE-2026-90679?
No fix has been published for CVE-2026-90679 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-90679 being exploited?
There is no known exploitation of CVE-2026-90679 in the wild and no public exploit code.
Sources
Also known as GHSA-5cjj-j77f-rq2g.