CVE-2026-55735

{"id": "CVE-2026-55735", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-55735", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-03T19:29:43.841542Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.2, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "affectedData": [{"cpes": ["cpe:2.3:a:ueberauth:guardian:*:*:*:*:*:*:*:*"], "repo": "https://github.com/ueberauth/guardian", "vendor": "ueberauth", "modules": ["'Elixir.Guardian'"], "product": "guardian", "versions": [{"status": "affected", "version": "1.0.0", "lessThan": "2.4.1", "versionType": "semver"}], "packageURL": "pkg:hex/guardian", "packageName": "guardian", "programFiles": ["lib/guardian.ex"], "collectionURL": "https://repo.hex.pm", "defaultStatus": "unaffected", "programRoutines": [{"name": "'Elixir.Guardian':revoke/3"}]}, {"cpes": ["cpe:2.3:a:ueberauth:guardian:*:*:*:*:*:*:*:*"], "repo": "https://github.com/ueberauth/guardian", "vendor": "ueberauth", "modules": ["'Elixir.Guardian'"], "product": "guardian", "versions": [{"status": "affected", "version": "d65227145f72b290106c06cecbe42728fbf05fe2", "lessThan": "2bd7a8c29770d423d855c0a4965caa6c3e486901", "versionType": "git"}], "packageURL": "pkg:github/ueberauth/guardian", "packageName": "ueberauth/guardian", "programFiles": ["lib/guardian.ex"], "collectionURL": "https://github.com", "defaultStatus": "unaffected", "programRoutines": [{"name": "'Elixir.Guardian':revoke/3"}]}]}], "published": "2026-08-01T19:16:42.510", "references": [{"url": "https://cna.erlef.org/cves/CVE-2026-55735.html", "tags": ["Third Party Advisory"], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/ueberauth/guardian/commit/2bd7a8c29770d423d855c0a4965caa6c3e486901", "tags": ["Patch"], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/ueberauth/guardian/security/advisories/GHSA-7975-hp3r-5qhv", "tags": ["Exploit", "Patch", "Vendor Advisory"], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://osv.dev/vulnerability/EEF-CVE-2026-55735", "tags": ["Third Party Advisory"], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/ueberauth/guardian/security/advisories/GHSA-7975-hp3r-5qhv", "tags": ["Exploit", "Patch", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "description": [{"lang": "en", "value": "CWE-347"}]}], "descriptions": [{"lang": "en", "value": "Improper Verification of Cryptographic Signature in ueberauth guardian allows an unauthenticated attacker to revoke a victim's session with a forged token.\n\nGuardian.revoke/3 in lib/guardian.ex decodes the supplied token with peek/1, which performs no signature verification (it only base64-decodes the JWT header and payload). The resulting unverified claims are forwarded directly to the configured token module's revoke callback and the implementation's on_revoke callback, a state-mutating sink. The sibling operations refresh/2 and exchange/4 both call decode_and_verify first, so the signature is checked before anything acts on the claims; revoke/3 is the only state-mutating path that acts on claims without verifying the signature.\n\nAn attacker who knows or guesses a victim's identifying claim values (jti, sub) can forge a JWT carrying those claims, sign it with an arbitrary key, and submit it to any endpoint that funnels a caller-supplied token into Guardian.revoke/3 (the standard logout / session-revocation pattern). When the token module mutates state keyed by the claims (whitelist deletion or blacklist insertion, for example a GuardianDb-style store), the victim's legitimate session is evicted. This is an unauthenticated session-revocation denial of service; the attacker never needs the signing secret.\n\nThis issue affects guardian: from 1.0.0 before 2.4.1."}], "lastModified": "2026-08-06T14:25:11.683", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:ueberauth:guardian:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D61141EA-5786-4D7B-8780-55707F97E793", "versionEndExcluding": "2.4.1", "versionStartIncluding": "1.0.0"}], "operator": "OR"}]}], "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}