team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13 Token Revocation token signature verification

Summaryinfo

A vulnerability was found in team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13 and classified as problematic. Affected by this issue is the function AshAuthentication.TokenResource.RevokeTokenChange.change of the component Token Revocation. Executing a manipulation of the argument token can lead to signature verification. This vulnerability is handled as CVE-2026-78223. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in team-alembic ash_authentication up to 4.14.0/5.0.0-rc.13. This vulnerability affects the function AshAuthentication.TokenResource.RevokeTokenChange.change of the component Token Revocation. The manipulation of the argument token with an unknown input leads to a signature verification vulnerability. The CWE definition for the vulnerability is CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. As an impact it is known to affect integrity. CVE summarizes:

Improper Verification of Cryptographic Signature vulnerability in team-alembic AshAuthentication allows a caller of the token revocation action to neutralise a revocation or write arbitrary rows into the token resource. AshAuthentication.TokenResource.RevokeTokenChange.change/3 reads the :token argument and decodes it with AshAuthentication.Jwt.peek/1, which delegates to Joken.peek_claims/1 and performs no signature check, unlike Jwt.verify/4. The jti, exp and sub claims it returns are written straight onto the revocation record, guarded only by byte_size(token) > 0. Because expires_at derives from the attacker-chosen exp, a forged copy of a genuine token that keeps the real jti but backdates exp yields a revocation row that is already expired: expunge_expired removes it and the genuine token passes revoked? again. Arbitrary jti and sub values can be inserted the same way. This issue affects ash_authentication: from 0.2.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-78223 since 09/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available.

Upgrading to version 4.15.0 or 5.0.0-rc.14 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• team-alembic

Name

• ash_authentication

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14.0
• 5.0.0-rc.0
• 5.0.0-rc.1
• 5.0.0-rc.2
• 5.0.0-rc.3
• 5.0.0-rc.4
• 5.0.0-rc.5
• 5.0.0-rc.6
• 5.0.0-rc.7
• 5.0.0-rc.8
• 5.0.0-rc.9
• 5.0.0-rc.10
• 5.0.0-rc.11
• 5.0.0-rc.12
• 5.0.0-rc.13

Website

• Product: https://github.com/team-alembic/ash_authentication/

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