Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-07-25T00:00:00 kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-191

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA mlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating software state and skipping hardware offload setup. That path jumps to the common success label before taking the eswitch mode block. After tunnel-mode validation was moved earlier, the common success label unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs, this decrements esw->offloads.num_block_mode without a matching increment. Return directly after installing the acquire SA offload handle, so only the paths that successfully called mlx5_eswitch_block_mode() call the matching unblock.

A flaw was found in the Linux kernel's mlx5e network driver. When handling temporary Security Associations (SAs) for IPsec, the `mlx5e_xfrm_add_state()` function incorrectly decrements a counter without a corresponding increment. This underflow in the eswitch mode block mechanism can lead to a denial of service, potentially disrupting network operations.

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64522 https://nvd.nist.gov/vuln/detail/CVE-2026-64522 https://lore.kernel.org/linux-cve-announce/2026072538-CVE-2026-64522-eb28@gregkh/T