{"id":"CVE-2026-78223","state":"PUBLISHED","title":"Token revocation record built from unverified JWT claims in AshAuthentication","description":"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.\n\nAshAuthentication.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.\n\nThis 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.","publishedAt":"2026-09-17T13:09:19.591Z","updatedAt":"2026-09-17T18:28:20.821Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","source":"EEF"},"assigner":"EEF","products":["team-alembic ash_authentication"],"affected":[{"vendor":"team-alembic","product":"ash_authentication","packageName":"ash_authentication","packageURL":"pkg:hex/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"4.15.0","versionType":"semver"},{"version":"5.0.0-rc.0","status":"affected","lessThan":"5.0.0-rc.14","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.TokenResource.RevokeTokenChange'"],"programFiles":["lib/ash_authentication/token_resource/revoke_token_change.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.TokenResource.RevokeTokenChange':change/3"}],"repo":"https://github.com/team-alembic/ash_authentication"},{"vendor":"team-alembic","product":"ash_authentication","packageName":"team-alembic/ash_authentication","packageURL":"pkg:github/team-alembic/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"a939dde9b917c072cdf10c4b0913a9886a4b0231","status":"affected","lessThan":"*","changes":[{"at":"344cebb12faf68e648d3283394073ba0c0f78459","status":"unaffected"},{"at":"eb86353fe5a547c5ff5fd9af0e2c212518c31c9b","status":"unaffected"}],"versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.TokenResource.RevokeTokenChange'"],"programFiles":["lib/ash_authentication/token_resource/revoke_token_change.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.TokenResource.RevokeTokenChange':change/3"}],"repo":"https://github.com/team-alembic/ash_authentication"}],"references":["https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-mfwg-5cpf-px58","https://cna.erlef.org/cves/CVE-2026-78223.html","https://osv.dev/vulnerability/EEF-CVE-2026-78223","https://github.com/team-alembic/ash_authentication/commit/a939dde9b917c072cdf10c4b0913a9886a4b0231","https://github.com/team-alembic/ash_authentication/commit/344cebb12faf68e648d3283394073ba0c0f78459","https://github.com/team-alembic/ash_authentication/commit/eb86353fe5a547c5ff5fd9af0e2c212518c31c9b"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/78xxx/CVE-2026-78223.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-78223","state":"PUBLISHED","datePublished":"2026-09-17T13:09:19.591Z","dateUpdated":"2026-09-17T18:28:20.821Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-09-11T18:30:01.328Z"},"containers":{"cna":{"title":"Token revocation record built from unverified JWT claims in AshAuthentication","descriptions":[{"lang":"en","value":"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.\n\nAshAuthentication.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.\n\nThis 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."}],"affected":[{"vendor":"team-alembic","product":"ash_authentication","packageName":"ash_authentication","packageURL":"pkg:hex/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"4.15.0","versionType":"semver"},{"version":"5.0.0-rc.0","status":"affected","lessThan":"5.0.0-rc.14","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.TokenResource.RevokeTokenChange'"],"programFiles":["lib/ash_authentication/token_resource/revoke_token_change.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.TokenResource.RevokeTokenChange':change/3"}],"repo":"https://github.com/team-alembic/ash_authentication"},{"vendor":"team-alembic","product":"ash_authentication","packageName":"team-alembic/ash_authentication","packageURL":"pkg:github/team-alembic/ash_authentication","defaultStatus":"unaffected","versions":[{"version":"a939dde9b917c072cdf10c4b0913a9886a4b0231","status":"affected","lessThan":"*","changes":[{"at":"344cebb12faf68e648d3283394073ba0c0f78459","status":"unaffected"},{"at":"eb86353fe5a547c5ff5fd9af0e2c212518c31c9b","status":"unaffected"}],"versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.TokenResource.RevokeTokenChange'"],"programFiles":["lib/ash_authentication/token_resource/revoke_token_change.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.TokenResource.RevokeTokenChange':change/3"}],"repo":"https://github.com/team-alembic/ash_authentication"}],"references":[{"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-mfwg-5cpf-px58","tags":["related","vendor-advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-78223.html","name":"EEF CNA record for CVE-2026-78223","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-78223","name":"OSV record EEF-CVE-2026-78223","tags":["related"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/a939dde9b917c072cdf10c4b0913a9886a4b0231","name":"Introducing commit a939dde in team-alembic/ash_authentication","tags":["related"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/344cebb12faf68e648d3283394073ba0c0f78459","name":"Fix commit 344cebb in team-alembic/ash_authentication","tags":["patch"]},{"url":"https://github.com/team-alembic/ash_authentication/commit/eb86353fe5a547c5ff5fd9af0e2c212518c31c9b","name":"Fix commit eb86353 in team-alembic/ash_authentication","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":6.9,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","description":"CWE-347 Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-09-17T13:09:19.591Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*","versionEndExcluding":"4.15.0","versionStartIncluding":"0.2.0","vulnerable":true},{"criteria":"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*","versionEndExcluding":"5.0.0-rc.14","versionStartIncluding":"5.0.0-rc.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"reporter","value":"Peter Ullrich"},{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"},{"lang":"en","type":"remediation developer","value":"James Harton"}],"dateAssigned":"2026-09-11T18:31:49.000Z","impacts":[{"capecId":"CAPEC-475","descriptions":[{"lang":"en","value":"CAPEC-475 Signature Spoofing by Improper 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