Bug 2507164 (CVE-2026-64522)

Summary: CVE-2026-64522 kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-25 10:08:26 UTC 
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.
Comment 1 TEJ RATHI 2026-07-29 13:19:00 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072538-CVE-2026-64522-eb28@gregkh/T