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[ CVE-2026-75806 · Published 29 Sep 2026 ]

Vulnerability in OpenSSL

CVSS 5.3 EPSS <1%2 agency advisoriesFix available

[ Description ]Official description

Issue summary: An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. Impact summary: An attacker who can send a datagram that is routed to an existing DTLS 1.2 association can tear that association down without knowing any key material. This is a Denial of Service limited to the targeted association. There is no memory safety or confidentiality impact. CWE: CWE-1284: Improper Validation of Specified Quantity in Input Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher suite carries an explicit IV followed by the ciphertext and an authentication tag. When decrypting such a record the record layer passed the record length to the cipher implementation before checking that the record was long enough to contain the explicit IV and the tag. For a record shorter than that overhead the cipher implementation rejected the impossible length, and the record layer treated this as an internal failure and raised a fatal internal_error alert instead of treating the record as one that failed authentication. In TLS 1.2 the same record causes a fatal internal_error alert instead of the expected bad_record_mac alert. Since any undecryptable record already terminates a TLS connection, this is a protocol conformance issue rather than a security issue in TLS. The fix validates the record length against the explicit IV and tag length before any AEAD processing, so that TLS reports bad_record_mac and DTLS silently discards the record. FIPS impact: no The affected code is outside the FIPS module boundary.

[ Fixes ]Fixes and patches

[ Advisories ]Government CERT advisories

  • CERT-FRCERTFR-2026-AVI-1241

    Multiple vulnerabilities in OpenSSL Translated from French

    Multiple vulnerabilities have been discovered in OpenSSL. Some of them allow an attacker to cause remote denial of service, a breach of data confidentiality and a breach of data integrity.

    CVE-2026-75806CVE-2026-77696CVE-2026-35189+11 more CVEs
  • BSI CERT-BundWID-SEC-2026-3638

    OpenSSL: Multiple vulnerabilities Translated from German

    Risk highCVE-2026-35189CVE-2026-84784CVE-2026-75805+11 more CVEs

[ References ]References