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CVE-2026-31469

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.2%
Linux•Linux•Versions : <fedd2e1630cac920844997227ccbe7b26a76375a, <=6.1.*, <=6.12.*, <c1ec36cb3768574b916f20d2d7415fd14fa1bf12, <f04733c4dc40c43899c3d1c97afbae5831a3770f, 0, 7.0, <2.6.26, <=5.10.*, <=6.6.*, 6.19.11, <=6.19.*, <9a18629f2525781f0f3dda7be72b204e4cf77d08, f2fc6a54585a1be6669613a31fbaba2ecbadcd36, 5.15.203, <=6.18.*, 6.6.131, 6.12.80, <8a4790850e710fd6771e4d2112168ed1dd6c0e54, <ba8bda9a0896746053aa97ac6c3e08168729172c, <=*, 5.10.253, <=5.15.*, 6.1.168, 6.18.21, 2.6.26, <63d45077b97bb0e0fe0c75931acbbca7a47af141, <be0e63f3b97bbaf453c542e8a15ba2a536e2ac01

Description

In the Linux kernel, the following vulnerability has been resolved: virtio_net: Fix UAF on dst_ops when IFF_XMIT_DST_RELEASE is cleared and napi_tx is false A UAF issue occurs when the virtio_net driver is configured with napi_tx=N and the device's IFF_XMIT_DST_RELEASE flag is cleared (e.g., during the configuration of tc route filter rules). When IFF_XMIT_DST_RELEASE is removed from the net_device, the network stack expects the driver to hold the reference to skb->dst until the packet is fully transmitted and freed. In virtio_net with napi_tx=N, skbs may remain in the virtio transmit ring for an extended period. If the network namespace is destroyed while these skbs are still pending, the corresponding dst_ops structure has freed. When a subsequent packet is transmitted, free_old_xmit() is triggered to clean up old skbs. It then calls dst_release() on the skb associated with the stale dst_entry. Since the dst_ops (referenced by the dst_entry) has already been freed, a UAF kernel paging request occurs. fix it by adds skb_dst_drop(skb) in start_xmit to explicitly release the dst reference before the skb is queued in virtio_net. Call Trace: Unable to handle kernel paging request at virtual address ffff80007e150000 CPU: 2 UID: 0 PID: 6236 Comm: ping Kdump: loaded Not tainted 7.0.0-rc1+ #6 PREEMPT ... percpu_counter_add_batch+0x3c/0x158 lib/percpu_counter.c:98 (P) dst_release+0xe0/0x110 net/core/dst.c:177 skb_release_head_state+0xe8/0x108 net/core/skbuff.c:1177 sk_skb_reason_drop+0x54/0x2d8 net/core/skbuff.c:1255 dev_kfree_skb_any_reason+0x64/0x78 net/core/dev.c:3469 napi_consume_skb+0x1c4/0x3a0 net/core/skbuff.c:1527 __free_old_xmit+0x164/0x230 drivers/net/virtio_net.c:611 [virtio_net] free_old_xmit drivers/net/virtio_net.c:1081 [virtio_net] start_xmit+0x7c/0x530 drivers/net/virtio_net.c:3329 [virtio_net] ... Reproduction Steps: NETDEV="enp3s0" config_qdisc_route_filter() { tc qdisc del dev $NETDEV root tc qdisc add dev $NETDEV root handle 1: prio tc filter add dev $NETDEV parent 1:0 \ protocol ip prio 100 route to 100 flowid 1:1 ip route add 192.168.1.100/32 dev $NETDEV realm 100 } test_ns() { ip netns add testns ip link set $NETDEV netns testns ip netns exec testns ifconfig $NETDEV 10.0.32.46/24 ip netns exec testns ping -c 1 10.0.32.1 ip netns del testns } config_qdisc_route_filter test_ns sleep 2 test_ns

Gravité et risque d'exploitation

CVE-2026-31469 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.18 %, ce qui la place devant 7.5 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <fedd2e1630cac920844997227ccbe7b26a76375a, <=6.1.*, <=6.12.*, <c1ec36cb3768574b916f20d2d7415fd14fa1bf12, <f04733c4dc40c43899c3d1c97afbae5831a3770f, 0, 7.0, <2.6.26, <=5.10.*, <=6.6.*, 6.19.11, <=6.19.*, <9a18629f2525781f0f3dda7be72b204e4cf77d08, f2fc6a54585a1be6669613a31fbaba2ecbadcd36, 5.15.203, <=6.18.*, 6.6.131, 6.12.80, <8a4790850e710fd6771e4d2112168ed1dd6c0e54, <ba8bda9a0896746053aa97ac6c3e08168729172c, <=*, 5.10.253, <=5.15.*, 6.1.168, 6.18.21, 2.6.26, <63d45077b97bb0e0fe0c75931acbbca7a47af141, <be0e63f3b97bbaf453c542e8a15ba2a536e2ac01) 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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