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ReviewHigh

CVE-2026-74663

Linux

In the Linux kernel, the following vulnerability has been resolved: net/sched: reject overly deep qdisc hierarchies Deep qdisc hierarchies can lead to excessive recursion in qdisc tree walkers and exhaust the kernel stack. The existing loop check does not cover the create-and-graft path, so a hierarchy can still be extended by creating a new child qdisc below an already deep parent. Store the hierarchy depth in struct Qdisc and update it when qdiscs are grafted. Reject new child qdiscs once the parent is already at the maximum allowed depth.

CVSS
7.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.08.23
PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: net/sched: reject overly deep qdisc hierarchies Deep qdisc hierarchies can lead to excessive recursion in qdisc tree walkers and exhaust the kernel stack. The existing loop check does not cover the create-and-graft path, so a hierarchy can still be extended by creating a new child qdisc below an already deep parent. Store the hierarchy depth in struct Qdisc and update it when qdiscs are grafted. Reject new child qdiscs once the parent is already at the maximum allowed depth.

Affected product and versions

Product
Linux
Affected versions
>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 08dc49df1527b09d9ea225a7265bbf6c237097bf, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a627d36c2a94e18c8c105ae68008786dfd85592e, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9f69bb9fdaa2fe64b68bb62fb84d405784bee540, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8ca8cdb74939581339e1ae370193c0adb5a85336, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2759acf08a3454866660edcd3ef4e64139f254a6, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a4b14a4df29d36458a943f9b521ddd0f940363cc, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e2d658c6427844cee5bc654b436ca68d680b6148, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dedd34b0f2310e28c5f6d4875cfbf4b7ed821c01, >= 2.6.12
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available