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CVE-2026-75806

Vulnérabilité moyenne dans OpenSSL (OpenSSL)

CVSS 5.3 · Moyenne
EPSS 0.4%
OpenSSL•OpenSSL•Versions : <3.5.9, <1.1.1zj, <3.0.23, 3.6.0, 3.0.0, 4.0.0, 1.1.1, 3.5.0, <4.0.3, <3.4.8, 3.4.0, <3.6.5

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.

Gravité et risque d'exploitation

CVE-2026-75806 obtient un score CVSS de 5.3/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.39 %, ce qui la place devant 31.3 % des CVE référencées.

Que faire ?

  • Vérifiez si OpenSSL (versions <3.5.9, <1.1.1zj, <3.0.23, 3.6.0, 3.0.0, 4.0.0, 1.1.1, 3.5.0, <4.0.3, <3.4.8, 3.4.0, <3.6.5) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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