CVE-2026-23277
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit through slave devices, but does not update skb->dev to the slave device beforehand. When a gretap tunnel is a TEQL slave, the transmit path reaches iptunnel_xmit() which saves dev = skb->dev (still pointing to teql0 master) and later calls iptunnel_xmit_stats(dev, pkt_len). This function does: get_cpu_ptr(dev->tstats) Since teql_master_setup() does not set dev->pcpu_stat_type to NETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats for teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes NULL + __per_cpu_offset[cpu], resulting in a page fault. BUG: unable to handle page fault for address: ffff8880e6659018 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 68bc067 P4D 68bc067 PUD 0 Oops: Oops: 0002 [#1] SMP KASAN PTI RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89) Call Trace: <TASK> ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847) __gre_xmit (net/ipv4/ip_gre.c:478) gre_tap_xmit (net/ipv4/ip_gre.c:779) teql_master_xmit (net/sched/sch_teql.c:319) dev_hard_start_xmit (net/core/dev.c:3887) sch_direct_xmit (net/sched/sch_generic.c:347) __dev_queue_xmit (net/core/dev.c:4802) neigh_direct_output (net/core/neighbour.c:1660) ip_finish_output2 (net/ipv4/ip_output.c:237) __ip_finish_output.part.0 (net/ipv4/ip_output.c:315) ip_mc_output (net/ipv4/ip_output.c:369) ip_send_skb (net/ipv4/ip_output.c:1508) udp_send_skb (net/ipv4/udp.c:1195) udp_sendmsg (net/ipv4/udp.c:1485) inet_sendmsg (net/ipv4/af_inet.c:859) __sys_sendto (net/socket.c:2206) Fix this by setting skb->dev = slave before calling netdev_start_xmit(), so that tunnel xmit functions see the correct slave device with properly allocated tstats.
Gravité et risque d'exploitation
CVE-2026-23277 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 0.13 %, ce qui la place devant 2.0 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.1.*, <6b1f563d670162e188a0f2aec39c24b67b106e17, <=6.12.*, 6.12.78, 0, 7.0, <57c153249143333bbf4ecf927bdf8aa2696ee397, <0bad9c86edd22dec4df83c2b29872d66fd8a2ff4, <59b06d8b9bdb6b64b3c534c18da68bce5ccd31be, 6.18.19, <=5.10.*, <=6.6.*, <=6.19.*, <4.5, 039f50629b7f860f36644ed1f34b27da9aa62f43, 5.15.203, 6.19.9, <=6.18.*, 6.1.167, <21ea283c2750c8307aa35ee832b0951cc993c27d, <=*, <383493b9940e3d1b5517424081b3e072e20ec43c, 4.5, 5.10.253, <=5.15.*, <81a43e8005366f16e629d8c95dfe05beaa8d36a7, <0cc0c2e661af418bbf7074179ea5cfffc0a5c466, 6.6.130) 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/383493b9940e3d1b5517424081b3e072e20ec43c
- https://git.kernel.org/stable/c/6b1f563d670162e188a0f2aec39c24b67b106e17
- https://git.kernel.org/stable/c/57c153249143333bbf4ecf927bdf8aa2696ee397
- https://git.kernel.org/stable/c/59b06d8b9bdb6b64b3c534c18da68bce5ccd31be
- https://git.kernel.org/stable/c/81a43e8005366f16e629d8c95dfe05beaa8d36a7
- https://git.kernel.org/stable/c/0bad9c86edd22dec4df83c2b29872d66fd8a2ff4
- https://git.kernel.org/stable/c/21ea283c2750c8307aa35ee832b0951cc993c27d
- https://git.kernel.org/stable/c/0cc0c2e661af418bbf7074179ea5cfffc0a5c466
