CVE-2026-74587

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.5%
Linux•Linux•Versions : <=6.1.*, <d949992bc3f00027a2c755e860a11950c75f6073, 3.0, <=6.12.*, 6.6.152, <07daf4f9750104960a1d60831b2353c0d41f35fb, 0, <=7.1.*, <e1bb114e09372fd6e03387ced9ef566da336ed6c, 5.15.216, <=5.10.*, <=6.6.*, 7.1.9, <618b5c6d049896fcfabb91afc072954c92cb2693, 6.1.183, <8c283e7b56adce00193837f3311b06662466fb21, <=6.18.*, <179676f0166230c80053a392303485b37c93dd33, 6.12.104, <10459b03e2d9ee12435e96f587de4d4cacdbf435, <3.0, 6.18.45, <=*, <=5.15.*, a000c01e60e40e15304ffe48fff051d17a7bea91, 5.10.265, 7.2, <dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix use-after-free of cached ASCONF chunk addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal ASCONF-ACK completion path releases the chunk and clears the pointer. However, sctp_asconf_queue_teardown() releases the cached chunk without clearing addip_last_asconf. During peer restart handling, sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes sctp_asconf_queue_teardown() while the association remains alive and leaves the pointer dangling. A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(), which accesses the stale chunk and passes it to sctp_process_asconf_ack(), causing a use-after-free and a second release. Clearing the pointer exposes a race with T4 expiry. Peer restart handling queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses timer_delete(), which does not wait for a callback already running on another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after the purge and dereference NULL. Clear addip_last_asconf after releasing the cached chunk, and make sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding ASCONF remains.

Gravité et risque d'exploitation

CVE-2026-74587 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 0.50 %, ce qui la place devant 41.5 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <d949992bc3f00027a2c755e860a11950c75f6073, 3.0, <=6.12.*, 6.6.152, <07daf4f9750104960a1d60831b2353c0d41f35fb, 0, <=7.1.*, <e1bb114e09372fd6e03387ced9ef566da336ed6c, 5.15.216, <=5.10.*, <=6.6.*, 7.1.9, <618b5c6d049896fcfabb91afc072954c92cb2693, 6.1.183, <8c283e7b56adce00193837f3311b06662466fb21, <=6.18.*, <179676f0166230c80053a392303485b37c93dd33, 6.12.104, <10459b03e2d9ee12435e96f587de4d4cacdbf435, <3.0, 6.18.45, <=*, <=5.15.*, a000c01e60e40e15304ffe48fff051d17a7bea91, 5.10.265, 7.2, <dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d) 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