{"id":"CVE-2026-34610","summary":"leancrypto: Integer truncation in X.509 name parser enables certificate identity impersonation","details":"The leancrypto library is a cryptographic library that exclusively contains only PQC-resistant cryptographic algorithms. Prior to version 1.7.1, lc_x509_extract_name_segment() casts size_t vlen to uint8_t when storing the Common Name (CN) length. An attacker who crafts a certificate with CN = victim's CN + 256 bytes padding gets cn_size = (uint8_t)(256 + N) = N, where N is the victim's CN length. The first N bytes of the attacker's CN are the victim's identity. After parsing, the attacker's certificate has an identical CN to the victim's — enabling identity impersonation in PKCS#7 verification, certificate chain matching, and code signing. 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1.7.1.","aliases":["GHSA-636g-jxv4-v4gr"],"modified":"2026-08-12T15:33:38.213963Z","published":"2026-04-02T17:54:53.250Z","related":["SUSE-SU-2026:21754-1","SUSE-SU-2026:21824-1","openSUSE-SU-2026:10563-1","openSUSE-SU-2026:20783-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-681"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34610.json"},"references":[{"type":"WEB","url":"https://github.com/smuellerDD/leancrypto/releases/tag/v1.7.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34610.json"},{"type":"ADVISORY","url":"https://github.com/smuellerDD/leancrypto/security/advisories/GHSA-636g-jxv4-v4gr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34610"},{"type":"FIX","url":"https://github.com/smuellerDD/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/smuellerdd/leancrypto","events":[{"introduced":"0"},{"fixed":"e7fa8c87a46c5787174c18fac385aa08eecdedd1"},{"fixed":"5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a"}],"database_specific":{"cpe":"cpe:2.3:a:leancrypto:leancrypto:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"1.7.1"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["v1.7.0","v1.6.0","v1.5.1","v1.5.0","v1.4.0","v1.3.0","v1.2.0","v1.1.0","v1.0.1","v1.0.0","v0.11.0","v0.10.1","v0.10.0","v0.9.2","v0.9.1","v0.9.0","v0.8.0","v0.7.0","v0.6.0","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.0","v0.3.0"],"database_specific":{"vanir_signatures":[{"source":"https://github.com/smuellerdd/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a","target":{"file":"apps/src/lc_x509_generator_checker.c"},"deprecated":false,"digest":{"line_hashes":["124191862719956782558136961530273640974","200797749888053937735051491502027892542","265433056675998543758919315339258404678","81731644021144318313444816115742547410","193110942495680251507657668675947654761","99119703350586295205780449598396500165","158301691224047526824146594388587688188","138403378418395875564693432982442128898","6167116348499338671957640894445413571","100276054511506642986565156091548849555","173188776841251032524955959483760296330","181708719538056443125126224615507362700","24393858040284068398688464978566042079","185856003732619017566339406583390629253","17588188155811904603627968064520408735","134701196775781236352038600315809454955","94052653544298409205828025784539587413","232475296642114060501983599006898665922","48272921591686728124261330057821041847","224139352403840643025745003683826944109","93239745015414764020561022174125778472","75416592499183447016930192859825864038","4133724299083108568819183880540298125","299500991761005054580268627648317620657","44992837790998201866048821333747739680","75416592499183447016930192859825864038","4133724299083108568819183880540298125","299500991761005054580268627648317620657","44992837790998201866048821333747739680","327843279686952144466643060719860557560","21461895812082296728381926349091699118","73946607311445223402540766680461695992","253802515548344564395965901386712199128","296358550953724600872628322422067633216","310380010046564596575595719156122650678","201250352444809683931279755445871892005","145232191078632187177348959553507322928","20944217715472891952363433420087798090","199467862868328396205287265907616633703","315093829086827002859632132461033551165","146074784206677649160447542667957206609","24742244162306987115250596855156776674","165333545913671750400265760502251592138","27649748978033403302523921132698692765","213559923841562864222725572028319792072","313997520397666585040700013946523737564","124475351102755474160529646534393606761"],"threshold":0.9},"id":"CVE-2026-34610-037e29f8","signature_type":"Line","signature_version":"v1"},{"signature_type":"Function","signature_version":"v1","source":"https://github.com/smuellerdd/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a","target":{"file":"asn1/src/x509_cert_parser.c","function":"x509_fabricate_name"},"deprecated":false,"digest":{"function_hash":"95621512291603765487214232841369329927","length":2802},"id":"CVE-2026-34610-2a1de38a"},{"target":{"file":"asn1/src/x509_cert_parser.c","function":"lc_x509_san_email"},"deprecated":false,"digest":{"function_hash":"199579829852206154320206206663427827936","length":335},"id":"CVE-2026-34610-2c44093b","signature_type":"Function","signature_version":"v1","source":"https://github.com/smuellerdd/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a"},{"target":{"file":"asn1/src/x509_cert_parser.c","function":"lc_x509_note_issuer"},"deprecated":false,"digest":{"function_hash":"205589613250558479195109282245066229891","length":479},"id":"CVE-2026-34610-3e13c076","signature_type":"Function","signature_version":"v1","source":"https://github.com/smuellerdd/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a"},{"deprecated":false,"digest":{"length":9320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