CVE-2026-34876

{"id": "CVE-2026-34876", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "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:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "published": "2026-04-02T16:16:26.180", "references": [{"url": "https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-ccm-finish-boundary-check/", "tags": ["Vendor Advisory"], "source": "cve@mitre.org"}, {"url": "https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/", "tags": ["Vendor Advisory"], "source": "cve@mitre.org"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-125"}]}], "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."}], "lastModified": "2026-04-07T12:14:22.150", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "11EB1D49-E6D0-407C-9798-C7E631B1A03D", "versionEndExcluding": "3.6.6", "versionStartIncluding": "3.1.0"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}