CVE-2026-22979

Description

In the Linux kernel, the following vulnerability has been resolved: net: fix memory leak in skb_segment_list for GRO packets When skb_segment_list() is called during packet forwarding, it handles packets that were aggregated by the GRO engine. Historically, the segmentation logic in skb_segment_list assumes that individual segments are split from a parent SKB and may need to carry their own socket memory accounting. Accordingly, the code transfers truesize from the parent to the newly created segments. Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this truesize subtraction in skb_segment_list() was valid because fragments still carry a reference to the original socket. However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed this behavior by ensuring that fraglist entries are explicitly orphaned (skb->sk = NULL) to prevent illegal orphaning later in the stack. This change meant that the entire socket memory charge remained with the head SKB, but the corresponding accounting logic in skb_segment_list() was never updated. As a result, the current code unconditionally adds each fragment's truesize to delta_truesize and subtracts it from the parent SKB. Since the fragments are no longer charged to the socket, this subtraction results in an effective under-count of memory when the head is freed. This causes sk_wmem_alloc to remain non-zero, preventing socket destruction and leading to a persistent memory leak. The leak can be observed via KMEMLEAK when tearing down the networking environment: unreferenced object 0xffff8881e6eb9100 (size 2048): comm "ping", pid 6720, jiffies 4295492526 backtrace: kmem_cache_alloc_noprof+0x5c6/0x800 sk_prot_alloc+0x5b/0x220 sk_alloc+0x35/0xa00 inet6_create.part.0+0x303/0x10d0 __sock_create+0x248/0x640 __sys_socket+0x11b/0x1d0 Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST packets constructed by GRO, the truesize adjustment is removed. The call to skb_release_head_state() must be preserved. As documented in commit cf673ed0e057 ("net: fix fraglist segmentation reference count leak"), it is still required to correctly drop references to SKB extensions that may be overwritten during __copy_skb_header().

Gravité et risque d'exploitation

CVE-2026-22979 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.14 %, ce qui la place devant 3.1 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions 6.9, <=6.1.*, <=6.12.*, 6.8.5, d225b0ac96dc40d7e8ae2bc227eb2c56e130975f, <3264881431e308b9c72cb8a0159d57a56d67dd79, 0, 6.6.26, 5.15.154, 6.1.161, <6.6.121, <=6.6.*, 6.18.6, <88bea149db2057112af3aaf63534b24fab5858ab, fc126c1d51e9552eacd2d717b9ffe9262a8a4cd6, <6.1.161, <0b27828ebd1ed3107d7929c3737adbe862e99e74, 5b3b67f731296027cceb3efad881ae281213f86f, <5.16, <=6.18.*, <c114a32a2e70b82d447f409f7ffcfa3058f9d5bd, <238e03d0466239410b72294b79494e43d4fabe77, 6.1.85, 6.12.66, <=*, 6.19, ed4cccef64c1d0d5b91e69f7a8a6697c3a865486, <6.9, 6.6.121, 2eeab8c47c3c0276e0746bc382f405c9a236a5ad) 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/0b27828ebd1ed3107d7929c3737adbe862e99e74
• https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab
• https://git.kernel.org/stable/c/3264881431e308b9c72cb8a0159d57a56d67dd79
• https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd
• https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77