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High severity7.8NVD Advisory· Published May 1, 2024· Updated May 12, 2026

CVE-2024-26951

CVE-2024-26951

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:

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

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

A use-after-free in WireGuard's netlink dump allows local attackers to cause a crash or possibly execute code.

Vulnerability

The vulnerability resides in the WireGuard netlink implementation. When all peers are removed via wg_peer_remove_all(), each peer is moved to a temporary stack list. If a netlink dump is resumed and the cursor points to a peer that has been removed, it will attempt to access freed memory, leading to a use-after-free condition [1].

Exploitation

Exploitation requires local access to the system and the ability to trigger a netlink dump while simultaneously removing all peers. No special privileges beyond those needed to configure WireGuard are necessary. The race condition can be triggered by a simple script as shown in the report.

Impact

The use-after-free results in a slab memory corruption, evidenced by a KASAN report. An attacker could potentially leverage this to cause a denial of service (system crash) or escalate privileges if they can control the freed memory.

Mitigation

The fix, which checks peer->is_dead instead of relying on an empty peer list, has been applied to the Linux kernel stable branches. Siemens has identified this CVE as affecting the SIMATIC S7-1500 TM MFP GNU/Linux subsystem and recommends updating the kernel [1].

References
  1. SSA-265688

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

97

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

9

News mentions

0

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