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Response snapshot Nov 3, 2026, 20:56 UTC

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VulnerabilityCVE-2026-64522

Linux kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA

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.

At a glance

Exploited
Not known
Severity
8.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-64522 (opens a new tab)

What happened

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.

Continue reading

Return directly after installing the acquire SA offload handle, so only the paths that successfully called mlx5_eswitch_block_mode() call the matching unblock.

Scores and how they were measured

CVSS base severity

8.8

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-64522 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 3). Linux kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA (CVE-2026-64522). https://kevwire.com/record/CVE-2026-64522

MLA

"Linux kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA (CVE-2026-64522)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2026-64522.

Chicago

KEVWire. "Linux kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA (CVE-2026-64522)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2026-64522.

Evidence summary (plain text)

Linux kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA (Jul 25, 2026).
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.
CVSS 8.8 (version 3.1; evidence as of Nov 3, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-64522).
Sources:
NVD CVE-2026-64522: https://nvd.nist.gov/vuln/detail/CVE-2026-64522
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T18:06:04.789Z&lastModEndDate=2026-11-03T19:40:57.574Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:35:57.416Z&lastModEndDate=2026-11-03T19:05:57.748Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:01:00.112Z&lastModEndDate=2026-11-03T18:35:55.788Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-64522.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Awaiting Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail