UBUNTU-CVE-2026-23440
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix race condition during IPSec ESN update In IPSec full offload mode, the device reports an ESN (Extended Sequence Number) wrap event to the driver. The driver validates this event by querying the IPSec ASO and checking that the esn_event_arm field is 0x0, which indicates an event has occurred. After handling the event, the driver must re-arm the context by setting esn_event_arm back to 0x1. A race condition exists in this handling path. After validating the event, the driver calls mlx5_accel_esp_modify_xfrm() to update the kernel's xfrm state. This function temporarily releases and re-acquires the xfrm state lock. So, need to acknowledge the event first by setting esn_event_arm to 0x1. This prevents the driver from reprocessing the same ESN update if the hardware sends events for other reason. Since the next ESN update only occurs after nearly 2^31 packets are received, there's no risk of missing an update, as it will happen long after this handling has finished. Processing the event twice causes the ESN high-order bits (esn_msb) to be incremented incorrectly. The driver then programs the hardware with this invalid ESN state, which leads to anti-replay failures and a complete halt of IPSec traffic. Fix this by re-arming the ESN event immediately after it is validated, before calling mlx5_accel_esp_modify_xfrm(). This ensures that any spurious, duplicate events are correctly ignored, closing the race window.
02 / AFFECTED SOFTWARE
Affected packages
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
7 explicit affected versions
12 explicit affected versions
10 explicit affected versions
51 explicit affected versions
13 explicit affected versions
26 explicit affected versions
18 explicit affected versions
14 explicit affected versions
11 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
10 explicit affected versions
19 explicit affected versions
10 explicit affected versions
6 explicit affected versions
24 explicit affected versions
10 explicit affected versions
37 explicit affected versions
26 explicit affected versions
7 explicit affected versions
40 explicit affected versions
20 explicit affected versions
13 explicit affected versions
44 explicit affected versions
35 explicit affected versions
18 explicit affected versions
45 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
52 explicit affected versions
1 explicit affected versions
21 explicit affected versions
7 explicit affected versions
16 explicit affected versions
10 explicit affected versions
48 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
11 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
1 explicit affected versions
34 explicit affected versions
7 explicit affected versions
17 explicit affected versions
12 explicit affected versions
10 explicit affected versions
12 explicit affected versions
41 explicit affected versions
16 explicit affected versions
17 explicit affected versions
27 explicit affected versions
10 explicit affected versions
37 explicit affected versions
10 explicit affected versions
11 explicit affected versions
13 explicit affected versions
39 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
26 explicit affected versions
10 explicit affected versions
13 explicit affected versions
29 explicit affected versions
13 explicit affected versions
12 explicit affected versions
41 explicit affected versions
40 explicit affected versions
8 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
20 explicit affected versions
19 explicit affected versions
11 explicit affected versions
5 explicit affected versions
12 explicit affected versions
11 explicit affected versions
7 explicit affected versions
16 explicit affected versions
5 explicit affected versions
10 explicit affected versions
26 explicit affected versions
39 explicit affected versions
35 explicit affected versions
48 explicit affected versions
11 explicit affected versions
10 explicit affected versions
13 explicit affected versions
46 explicit affected versions
16 explicit affected versions
50 explicit affected versions
3 explicit affected versions
7 explicit affected versions
15 explicit affected versions
16 explicit affected versions
18 explicit affected versions
43 explicit affected versions
12 explicit affected versions
7 explicit affected versions
27 explicit affected versions
43 explicit affected versions
8 explicit affected versions
46 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
8 explicit affected versions
12 explicit affected versions
9 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
45 explicit affected versions
37 explicit affected versions
50 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
17 explicit affected versions
11 explicit affected versions
39 explicit affected versions
6 explicit affected versions
7 explicit affected versions
4 explicit affected versions
10 explicit affected versions
1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
16 explicit affected versions
10 explicit affected versions
8 explicit affected versions
45 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
14 explicit affected versions
11 explicit affected versions
1 explicit affected versions
19 explicit affected versions
39 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix race condition during IPSec ESN update In IPSec full offload mode, the device reports an ESN (Extended Sequence Number) wrap event to the driver. The driver validates this event by querying the IPSec ASO and checking that the esn_event_arm field is 0x0, which indicates an event has occurred. After handling the event, the driver must re-arm the context by setting esn_event_arm back to 0x1. A race condition exists in this handling path. After validating the event, the driver calls mlx5_accel_esp_modify_xfrm() to update the kernel's xfrm state. This function temporarily releases and re-acquires the xfrm state lock. So, need to acknowledge the event first by setting esn_event_arm to 0x1. This prevents the driver from reprocessing the same ESN update if the hardware sends events for other reason. Since the next ESN update only occurs after nearly 2^31 packets are received, there's no risk of missing an update, as it will happen long after this handling has finished. Processing the event twice causes the ESN high-order bits (esn_msb) to be incremented incorrectly. The driver then programs the hardware with this invalid ESN state, which leads to anti-replay failures and a complete halt of IPSec traffic. Fix this by re-arming the ESN event immediately after it is validated, before calling mlx5_accel_esp_modify_xfrm(). This ensures that any spurious, duplicate events are correctly ignored, closing the race window.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/beb6e2e5976a128b0cccf10d158124422210c5ef
- https://git.kernel.org/stable/c/2051c709dce92da3550040aa7949cd5a9c89b14e
- https://git.kernel.org/stable/c/3dffc083292e6872787bd7e34b957627622f9af4
- https://git.kernel.org/stable/c/8d625c15471fb8780125eaef682983a96af77bdc
- https://git.kernel.org/stable/c/96c9c25b74686ac2de15921c9ad30c5ef13af8cd
- https://git.kernel.org/stable/c/beb6e2e5976a128b0cccf10d158124422210c5ef
- https://ubuntu.com/security/CVE-2026-23440
- https://ubuntu.com/security/notices/USN-8567-1
- https://ubuntu.com/security/notices/USN-8574-1
- https://ubuntu.com/security/notices/USN-8574-2
- https://ubuntu.com/security/notices/USN-8574-3
- https://ubuntu.com/security/notices/USN-8595-1
- https://ubuntu.com/security/notices/USN-8595-2
- https://ubuntu.com/security/notices/USN-8595-3
- https://ubuntu.com/security/notices/USN-8596-1
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8608-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://www.cve.org/CVERecord?id=CVE-2026-23440