Description
In the Linux kernel, the following vulnerability has been resolved:

xsk: validate metadata when processing requests

The zero-copy path validates TX metadata while obtaining the descriptor
context, then reads it again later when preparing the hardware request.
User space can change the metadata between those operations and bypass the
original validation.

Validate the metadata in xsk_tx_metadata_request() and use the resulting
flags snapshot for every feature check. Read request fields once so all
zero-copy drivers process only values observed after successful
validation.
Published: 2026-08-22
Score: 7.8 High
EPSS: < 1% Very Low
KEV: No
Impact: Bypass Validation
Action: Apply Patch
AI Analysis

Impact

The vulnerability exists in the Linux kernel’s zero‑copy transmit path. When a transmit request is processed, the kernel validates transmit metadata while holding the descriptor context, then reads the same metadata again later when building the hardware request. The two reads are not synchronised, allowing a user to change the metadata in user space between the initial validation and the subsequent use. This race condition means that unvalidated metadata can end up driving the hardware request, effectively bypassing the kernel’s intended security checks on packet transmission.

Affected Systems

Linux kernel builds that lack the commit that introduces the validation fix are affected. Because no specific version numbers are provided, all kernel releases before the inclusion of the patch are potentially vulnerable. Any distribution shipping an unpatched kernel is therefore impacted.

Risk and Exploitability

The CVSS score of 7.8 indicates high severity. The EPSS <1% suggests that, at the of this assessment, the likelihood of exploitation is low. The vulnerability is not listed in the CISA KEV catalog. Based on the description, it is inferred that a local user with access to the zero‑copy transmit API can exploit the race condition by modifying the metadata between the initial check and its later use, thereby bypassing validation. The attack requires local user privileges and does not necessitate higher privileges.

Generated by OpenCVE AI on August 25, 2026 at 18:27 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the kernel patch that implements validation in xsk_tx_metadata_request() (commit 0cc7aa6e0d19027fdd42e6fbd156267ac1e3bbba).
  • If an immediate kernel upgrade is not possible, restrict unprivileged access to the zero‑copy transmit API by adjusting file permissions or capabilities.
  • As a temporary protective measure, suspend zero‑copy drivers or related kernel features until the patch can be deployed.

Generated by OpenCVE AI on August 25, 2026 at 18:27 UTC.

Tracking

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Advisories

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History

Tue, 25 Aug 2026 15:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-362

Tue, 25 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-367
References
Metrics threat_severity

None

threat_severity

Moderate


Tue, 25 Aug 2026 08:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-362

Tue, 25 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


Sat, 22 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: xsk: validate metadata when processing requests The zero-copy path validates TX metadata while obtaining the descriptor context, then reads it again later when preparing the hardware request. User space can change the metadata between those operations and bypass the original validation. Validate the metadata in xsk_tx_metadata_request() and use the resulting flags snapshot for every feature check. Read request fields once so all zero-copy drivers process only values observed after successful validation.
Title xsk: validate metadata when processing requests
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-25T05:41:50.013Z

Reserved: 2026-08-15T05:44:03.927Z

Link: CVE-2026-74707

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-22T16:16:45.433

Modified: 2026-08-25T06:18:55.180

Link: CVE-2026-74707

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-22T00:00:00Z

Links: CVE-2026-74707 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-25T18:30:04Z

Weaknesses
  • CWE-367

    Time-of-check Time-of-use (TOCTOU) Race Condition