Vulnerability-Lookup

GHSA-943R-726H-FC9X

Vulnerability from github – Published: 2026-04-03 18:31 – Updated: 2026-04-23 21:31

Details

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

net: shaper: protect from late creation of hierarchy

We look up a netdev during prep of Netlink ops (pre- callbacks) and take a ref to it. Then later in the body of the callback we take its lock or RCU which are the actual protections.

The netdev may get unregistered in between the time we take the ref and the time we lock it. We may allocate the hierarchy after flush has already run, which would lead to a leak.

Take the instance lock in pre- already, this saves us from the race and removes the need for dedicated lock/unlock callbacks completely. After all, if there's any chance of write happening concurrently with the flush - we're back to leaking the hierarchy.

We may take the lock for devices which don't support shapers but we're only dealing with SET operations here, not taking the lock would be optimizing for an error case.

Severity

5.5 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23436"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-03T16:16:25Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: shaper: protect from late creation of hierarchy\n\nWe look up a netdev during prep of Netlink ops (pre- callbacks)\nand take a ref to it. Then later in the body of the callback\nwe take its lock or RCU which are the actual protections.\n\nThe netdev may get unregistered in between the time we take\nthe ref and the time we lock it. We may allocate the hierarchy\nafter flush has already run, which would lead to a leak.\n\nTake the instance lock in pre- already, this saves us from the race\nand removes the need for dedicated lock/unlock callbacks completely.\nAfter all, if there\u0027s any chance of write happening concurrently\nwith the flush - we\u0027re back to leaking the hierarchy.\n\nWe may take the lock for devices which don\u0027t support shapers but\nwe\u0027re only dealing with SET operations here, not taking the lock\nwould be optimizing for an error case.",
  "id": "GHSA-943r-726h-fc9x",
  "modified": "2026-04-23T21:31:18Z",
  "published": "2026-04-03T18:31:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23436"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/719f6784f918f9e32f3ff3b197f900e852223f9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d22921727023e7852704965e935f4d1fc83a5ec9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d75ec7e8ba1979a1eb0b9211d94d749cdce849c8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-23436 (GCVE-0-2026-23436)

Vulnerability from cvelistv5 – Published: 2026-04-03 15:15 – Updated: 2026-05-11 22:06

Title

net: shaper: protect from late creation of hierarchy

Summary

In the Linux kernel, the following vulnerability has been resolved: net: shaper: protect from late creation of hierarchy We look up a netdev during prep of Netlink ops (pre- callbacks) and take a ref to it. Then later in the body of the callback we take its lock or RCU which are the actual protections. The netdev may get unregistered in between the time we take the ref and the time we lock it. We may allocate the hierarchy after flush has already run, which would lead to a leak. Take the instance lock in pre- already, this saves us from the race and removes the need for dedicated lock/unlock callbacks completely. After all, if there's any chance of write happening concurrently with the flush - we're back to leaking the hierarchy. We may take the lock for devices which don't support shapers but we're only dealing with SET operations here, not taking the lock would be optimizing for an error case.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6665 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/719f6784f918f9e32…
https://git.kernel.org/stable/c/d22921727023e7852…
https://git.kernel.org/stable/c/d75ec7e8ba1979a1e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 93954b40f6a4fc43226c01a15b02732f884500f1 , < 719f6784f918f9e32f3ff3b197f900e852223f9d (git) Affected: 93954b40f6a4fc43226c01a15b02732f884500f1 , < d22921727023e7852704965e935f4d1fc83a5ec9 (git) Affected: 93954b40f6a4fc43226c01a15b02732f884500f1 , < d75ec7e8ba1979a1eb0b9211d94d749cdce849c8 (git)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (semver) Unaffected: 6.18.20 , ≤ 6.18.* (semver) Unaffected: 6.19.10 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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JSON

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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "Documentation/netlink/specs/net_shaper.yaml",
            "net/shaper/shaper.c",
            "net/shaper/shaper_nl_gen.c",
            "net/shaper/shaper_nl_gen.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            },
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          "versions": [
            {
              "status": "affected",
              "version": "6.13"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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            },
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        }
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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