CVE-2026-90679

MEDIUM
4.3
CVSS Score
Published: September 13, 2026 at 03:55 AM UTC
Updated: September 22, 2026 at 08:11 PM UTC
1 product affected across 1 vendorForgejo

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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 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. 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

13.0.0 ≤ v ≤ 16.0.413.0.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMmitre
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-348

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