CVE-2026-72021

Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: use parsed transport offset in SCTP state lookup set_sctp_state() reads the SCTP chunk header again in order to drive the IPVS SCTP state table. For IPv6 it computes the offset with sizeof(struct ipv6hdr), while the surrounding IPVS code uses iph.len from ip_vs_fill_iph_skb(), where ipv6_find_hdr() has already skipped extension headers and found the real transport header. This makes the state machine read from the wrong offset for IPv6 SCTP packets that carry extension headers. For example, an INIT packet with an 8-byte destination options header can be scheduled correctly by sctp_conn_schedule(), but set_sctp_state() reads the first byte of the SCTP verification tag as a DATA chunk type. The connection then moves from NONE to ESTABLISHED instead of INIT1, gets the longer established timeout, and updates the active/inactive destination counters incorrectly. This happens even though the SCTP handshake has not completed. Use the parsed transport offset passed down from ip_vs_set_state() for the SCTP chunk-header lookup. For IPv4 and IPv6 packets without extension headers this preserves the existing offset.

Gravité et risque d'exploitation

CVE-2026-72021 obtient un score CVSS de 8.2/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.59 %, ce qui la place devant 47.1 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <247d055504dcc852e539b9f7f30d19f9741474bf, <=6.1.*, 6.18.40, <=6.12.*, 7.1.5, <a4a2d2e483d79cc2ad3a170674cf159644acf22b, 0, <=7.1.*, <2.6.34, 6.1.178, <=5.10.*, <9cb5ac594ca76d3a71803b23b74c835b0721e628, <=6.6.*, 6.12.97, 2.6.34, <d2b8b1557ec07ea1bb5dddbceaf4dfe63d388e27, <=6.18.*, 5.15.212, <290e9e8389b556efc603522e28bd1543846aa336, 5.10.261, 6.6.145, <e5d0bb8871668f20de8f3c94b5ae3f372346bc6e, <9f94573ab962a9e81954b755da016fa3cd2f5039, <=*, <=5.15.*, <2f75c0faa3361b28e36cc0512b3299e163e25789, 7.2, 2906f66a5682e5670a5eefe991843689b8d8563f) 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/d2b8b1557ec07ea1bb5dddbceaf4dfe63d388e27
• https://git.kernel.org/stable/c/9f94573ab962a9e81954b755da016fa3cd2f5039
• https://git.kernel.org/stable/c/290e9e8389b556efc603522e28bd1543846aa336
• https://git.kernel.org/stable/c/9cb5ac594ca76d3a71803b23b74c835b0721e628
• https://git.kernel.org/stable/c/a4a2d2e483d79cc2ad3a170674cf159644acf22b
• https://git.kernel.org/stable/c/247d055504dcc852e539b9f7f30d19f9741474bf
• https://git.kernel.org/stable/c/e5d0bb8871668f20de8f3c94b5ae3f372346bc6e
• https://git.kernel.org/stable/c/2f75c0faa3361b28e36cc0512b3299e163e25789