CVE-2025-39682

Description

In the Linux kernel, the following vulnerability has been resolved: tls: fix handling of zero-length records on the rx_list Each recvmsg() call must process either - only contiguous DATA records (any number of them) - one non-DATA record If the next record has different type than what has already been processed we break out of the main processing loop. If the record has already been decrypted (which may be the case for TLS 1.3 where we don't know type until decryption) we queue the pending record to the rx_list. Next recvmsg() will pick it up from there. Queuing the skb to rx_list after zero-copy decrypt is not possible, since in that case we decrypted directly to the user space buffer, and we don't have an skb to queue (darg.skb points to the ciphertext skb for access to metadata like length). Only data records are allowed zero-copy, and we break the processing loop after each non-data record. So we should never zero-copy and then find out that the record type has changed. The corner case we missed is when the initial record comes from rx_list, and it's zero length.

Gravité et risque d'exploitation

CVE-2025-39682 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 2.88 %, ce qui la place devant 86.6 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 6.12.44, <=6.16.*, 6.17, 0, <3439c15ae91a517cf3c650ea15a8987699416ad9, <29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e, 6.6.103, 84c61fe1a75b4255df1e1e7c054c9e6d048da417, <62708b9452f8eb77513115b17c4f8d1a22ebf843, <=6.6.*, 6.0, <2902c3ebcca52ca845c03182000e8d71d3a5196f, <6.0, 6.1.149, <c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677, <=*, 6.16.4) 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

• https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f
• https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677
• https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9
• https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e
• https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843