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CVE-2021-46999

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.7%
Linux•Linux•Versions : <=5.11.*, 5.11.22, <4.19.191, 0, 5.10.38, 5.4.41, <5.7, <35b4f24415c854cd718ccdf38dbea6297f010aae, <=5.10.*, 5.6.13, db8bf823e70f239372c62f13e4eb6f08a1665e8c, 5.4.120, <=5.4.*, 5.13, <61b877bad9bb0d82b7d8841be50872557090a704, <=4.19.*, <=5.12.*, 4.19.123, <b1b31948c0af44628e43353828453461bb74098f, 145cb2f7177d94bc54563ed26027e952ee0ae03c, <5.4.120, 5.7, <d624f2991b977821375fbd56c91b0c91d456a697, 4.19.191, <=*, a5ce8531ea508d270822b2bc6140c6198c8a2a7b, a204d577be70e0a0a6023cf1b9859c9ebffaeecd, <0bfd913c2121b3d553bfd52810fe6061d542d625, 5.12.5, <f01988ecf3654f805282dce2d3bb9afe68d2691e

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: do asoc update earlier in sctp_sf_do_dupcook_a There's a panic that occurs in a few of envs, the call trace is as below: [] general protection fault, ... 0x29acd70f1000a: 0000 [#1] SMP PTI [] RIP: 0010:sctp_ulpevent_notify_peer_addr_change+0x4b/0x1fa [sctp] [] sctp_assoc_control_transport+0x1b9/0x210 [sctp] [] sctp_do_8_2_transport_strike.isra.16+0x15c/0x220 [sctp] [] sctp_cmd_interpreter.isra.21+0x1231/0x1a10 [sctp] [] sctp_do_sm+0xc3/0x2a0 [sctp] [] sctp_generate_timeout_event+0x81/0xf0 [sctp] This is caused by a transport use-after-free issue. When processing a duplicate COOKIE-ECHO chunk in sctp_sf_do_dupcook_a(), both COOKIE-ACK and SHUTDOWN chunks are allocated with the transort from the new asoc. However, later in the sideeffect machine, the old asoc is used to send them out and old asoc's shutdown_last_sent_to is set to the transport that SHUTDOWN chunk attached to in sctp_cmd_setup_t2(), which actually belongs to the new asoc. After the new_asoc is freed and the old asoc T2 timeout, the old asoc's shutdown_last_sent_to that is already freed would be accessed in sctp_sf_t2_timer_expire(). Thanks Alexander and Jere for helping dig into this issue. To fix it, this patch is to do the asoc update first, then allocate the COOKIE-ACK and SHUTDOWN chunks with the 'updated' old asoc. This would make more sense, as a chunk from an asoc shouldn't be sent out with another asoc. We had fixed quite a few issues caused by this.

Gravité et risque d'exploitation

CVE-2021-46999 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 0.74 %, ce qui la place devant 53.9 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=5.11.*, 5.11.22, <4.19.191, 0, 5.10.38, 5.4.41, <5.7, <35b4f24415c854cd718ccdf38dbea6297f010aae, <=5.10.*, 5.6.13, db8bf823e70f239372c62f13e4eb6f08a1665e8c, 5.4.120, <=5.4.*, 5.13, <61b877bad9bb0d82b7d8841be50872557090a704, <=4.19.*, <=5.12.*, 4.19.123, <b1b31948c0af44628e43353828453461bb74098f, 145cb2f7177d94bc54563ed26027e952ee0ae03c, <5.4.120, 5.7, <d624f2991b977821375fbd56c91b0c91d456a697, 4.19.191, <=*, a5ce8531ea508d270822b2bc6140c6198c8a2a7b, a204d577be70e0a0a6023cf1b9859c9ebffaeecd, <0bfd913c2121b3d553bfd52810fe6061d542d625, 5.12.5, <f01988ecf3654f805282dce2d3bb9afe68d2691e) 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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