CVE-2025-21629
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets The blamed commit disabled hardware offoad of IPv6 packets with extension headers on devices that advertise NETIF_F_IPV6_CSUM, based on the definition of that feature in skbuff.h: * * - %NETIF_F_IPV6_CSUM * - Driver (device) is only able to checksum plain * TCP or UDP packets over IPv6. These are specifically * unencapsulated packets of the form IPv6|TCP or * IPv6|UDP where the Next Header field in the IPv6 * header is either TCP or UDP. IPv6 extension headers * are not supported with this feature. This feature * cannot be set in features for a device with * NETIF_F_HW_CSUM also set. This feature is being * DEPRECATED (see below). The change causes skb_warn_bad_offload to fire for BIG TCP packets. [ 496.310233] WARNING: CPU: 13 PID: 23472 at net/core/dev.c:3129 skb_warn_bad_offload+0xc4/0xe0 [ 496.310297] ? skb_warn_bad_offload+0xc4/0xe0 [ 496.310300] skb_checksum_help+0x129/0x1f0 [ 496.310303] skb_csum_hwoffload_help+0x150/0x1b0 [ 496.310306] validate_xmit_skb+0x159/0x270 [ 496.310309] validate_xmit_skb_list+0x41/0x70 [ 496.310312] sch_direct_xmit+0x5c/0x250 [ 496.310317] __qdisc_run+0x388/0x620 BIG TCP introduced an IPV6_TLV_JUMBO IPv6 extension header to communicate packet length, as this is an IPv6 jumbogram. But, the feature is only enabled on devices that support BIG TCP TSO. The header is only present for PF_PACKET taps like tcpdump, and not transmitted by physical devices. For this specific case of extension headers that are not transmitted, return to the situation before the blamed commit and support hardware offload. ipv6_has_hopopt_jumbo() tests not only whether this header is present, but also that it is the only extension header before a terminal (L4) header.
Gravité et risque d'exploitation
CVE-2025-21629 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 0.43 %, ce qui la place devant 35.8 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 9f605135a5c0fe614c2b15197b9ced1e217eca59, 6.12, <5.11, 6.11.7, <=6.1.*, <=6.12.*, 477b35d94a21530046fe91589960732fcf2b29ed, 6.1.116, 6.6.60, <6.1.124, 705350fbd6ed4b5d89ee045fa57a0594a72b17d7, 5.4.285, 0, 04c20a9356f283da623903e81e7c6d5df7e4dc3c, bcefc3cd7f592a70fcbbbfd7ad1fbc69172ea78b, a27a5c40ee4cbe00294e2c76160de5f2589061ba, <4.20, <=6.6.*, 6.12.9, 6.13, <6.12, c69bc67c1cb211aa390bea6e512bb01b1241fefb, <68e068cabd2c6c533ef934c2e5151609cf6ecc6d, <5.5, <5.16, 6.1.124, a84978a9cda68f0afe3f01d476c68db21526baf1, 4.19.323, 6.6.70, <d3b7a9c7597b779039a51d7b34116fbe424bf2b7, 5.10.229, <6.6.70, <=*, 5.15.171, <ac9cfef69565021c9e1022a493a9c40b03e2caf9, <95ccf006bbc8b59044313b8c309dcf29c546abd4) 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.