Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV L H L N U N N H 4.7 .0021 9.9 —
AFFECTED Product Versions Fixed Linux fef06678931ff67b158d337b581e5cf5ca40a3a3 – — Linux 6.4 – 6.6.130
TIMELINE Jan 13 Reserved by Linux Apr 3 Published (CNA: Linux) Oct 16 RESCORED — CVE-2026-23440 (Linux). CVSS 7.5 → 4.7 (NVD).
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.
| Date | Event | Detail |
|---|---|---|
| January 13, 2026 | Reserved | Reserved by Linux |
| April 3, 2026 | Published | Published (CNA: Linux) |
| October 16, 2026 | RESCORED | RESCORED — CVE-2026-23440 (Linux). CVSS 7.5 → 4.7 (NVD). |
Authoritative record: CVE-2026-23440 at cve.org
Vendors: linux
Weaknesses: CWE-362
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-23440 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
