{"dataType":"CVE_RECORD","cveMetadata":{"state":"PUBLISHED","cveId":"CVE-2026-34876","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","assignerShortName":"mitre","dateUpdated":"2026-04-02T15:54:45.230Z","dateReserved":"2026-03-31T00:00:00.000Z","datePublished":"2026-04-02T00:00:00.000Z"},"containers":{"cna":{"providerMetadata":{"orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","shortName":"mitre","dateUpdated":"2026-04-02T15:08:59.859Z"},"descriptions":[{"lang":"en","value":"An issue was discovered in Mbed TLS 3.x before 3.6.6. An out-of-bounds read vulnerability in mbedtls_ccm_finish() in library/ccm.c allows attackers to obtain adjacent CCM context data via invocation of the multipart CCM API with an oversized tag_len parameter. This is caused by missing validation of the tag_len parameter against the size of the internal 16-byte authentication buffer. The issue affects the public multipart CCM API in Mbed TLS 3.x, where mbedtls_ccm_finish() can be invoked directly by applications. In Mbed TLS 4.x versions prior to the fix, the same missing validation exists in the internal implementation; however, the function is not exposed as part of the public API. Exploitation requires application-level invocation of the multipart CCM API."}],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"references":[{"url":"https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/"},{"url":"https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ccm-finish-boundary-check/"}],"problemTypes":[{"descriptions":[{"type":"text","lang":"en","description":"n/a"}]}]},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","cweId":"CWE-125","lang":"en","description":"CWE-125 Out-of-bounds Read"}]}],"metrics":[{"cvssV3_1":{"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:H/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-04-02T15:53:54.288854Z","id":"CVE-2026-34876","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-02T15:54:45.230Z"}}]},"dataVersion":"5.2"}