CVE-2024-26951: wireguard: netlink: check for dangling peer via is_dead instead of empty list

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-01 · updated 2026-10-15
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: wireguard: netlink: check for dangling peer via is_dead instead of empty list If all peers are removed via wg_peer_remove_all(), rather than setting peer_list to empty, the peer is added to a temporary list with a head on the stack of wg_peer_remove_all(). If a netlink dump is resumed and the cursored peer is one that has been removed via wg_peer_remove_all(), it will iterate from that peer and then attempt to dump freed peers. Fix this by instead checking peer->is_dead, which was explictly created for this purpose. Also move up the device_update_lock lockdep assertion, since reading is_dead relies on that. It can be reproduced by a small script like: echo "Setting config..." ip link add dev wg0 type wireguard wg setconf wg0 /big-config ( while true; do echo "Showing config..." wg showconf wg0 > /dev/null done ) & sleep 4 wg setconf wg0 <(printf "[Peer]\nPublicKey=$(wg genkey)\n") Resulting in: BUG: KASAN: slab-use-after-free in __lock_acquire+0x182a/0x1b20 Read of size 8 at addr ffff88811956ec70 by task wg/59 CPU: 2 PID: 59 Comm: wg Not tainted 6.8.0-rc2-debug+ #5 Call Trace: <TASK> dump_stack_lvl+0x47/0x70 print_address_description.constprop.0+0x2c/0x380 print_report+0xab/0x250 kasan_report+0xba/0xf0 __lock_acquire+0x182a/0x1b20 lock_acquire+0x191/0x4b0 down_read+0x80/0x440 get_peer+0x140/0xcb0 wg_get_device_dump+0x471/0x1130

Affected products

Debian Linux: 10.0
Linux kernel: from 5.6 before 5.10.215; from 5.11 before 5.15.154; from 5.16 before 6.1.84; from 6.2 before 6.6.24; from 6.7 before 6.7.12; from 6.8 before 6.8.3 — fixed in 5.10.215, 5.15.154, 6.1.84, 6.6.24, 6.7.12, 6.8.3

How to fix

Upgrade to a fixed version: Linux kernel 5.10.215, 5.15.154, 6.1.84, 6.6.24. Check the vendor advisory for mitigations.

References

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