CVE-2026-90679 - Forgejo ActivityPub Identity Spoofing Vulnerability
Brief
CVE ID : CVE-2026-90679
Published : Sept. 13, 2026, 4:17 a. m.
- 35 minutes ago
Description : Forgejo 13.
- 0 through 16.
- 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 ActivityPubactivity 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.