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CVE-2026-75806 on Cyberus Linux 26.05

Aliases: CVE-2026-75806

Packages: openssl_3_6

Status: Resolved

Advisory Information

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.

Updates

2026-10-09 02:48 CEST

Metadata changes:

  • Status for package openssl_3_6: “Resolved” (257cd5b258336d6254b2bf4b5c12156b7b8f8821)

2026-10-05 16:30 CEST

Metadata changes:

  • Status for package openssl_3_6: “In Progress” (257cd5b258336d6254b2bf4b5c12156b7b8f8821)

(Amended on: 2026-10-05 16:31 CEST)

2026-10-05 16:28 CEST

Metadata changes:

  • Status for package openssl_3: “Package not supported” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

Comment:

OpenSSL 3.0 has reached EOL status and will not receive further security updates.

2026-10-05 16:27 CEST

Metadata changes:

  • Status for package openssl_3_5: “Resolved” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-05 16:27 CEST

Metadata changes:

  • Status for package openssl_4_0: “Resolved” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-01 01:19 CEST

Metadata changes:

  • Status for package openssl_3_5: “In Progress” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-01 01:18 CEST

Metadata changes:

  • Status for package openssl_4_0: “In Progress” (77f391603c7ef9448f3b3cb5d9aa3b01783836d6)

2026-09-30 09:55 CEST

Metadata changes:

  • Status for package openssl_3_5: “In Progress” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-09-29 19:52 CEST

Metadata changes:

  • Status for package openssl_3: “Plausible”
  • Status for package openssl_3_5: “Plausible”
  • Status for package openssl_3_6: “Plausible”
  • Status for package openssl_4_0: “Plausible”

(Amended on: 2026-09-29 19:53 CEST)

2026-09-29 19:24 CEST

Metadata changes:

  • Status for package openssl_3: “New”
  • Status for package openssl_3_5: “New”
  • Status for package openssl_3_6: “New”
  • Status for package openssl_4_0: “New”