Vulnerability-Lookup

GHSA-3CWP-73F3-J7W3

Vulnerability from github – Published: 2026-03-20 09:32 – Updated: 2026-03-20 09:32

Details

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

netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels

IDLETIMER revision 0 rules reuse existing timers by label and always call mod_timer() on timer->timer.

If the label was created first by revision 1 with XT_IDLETIMER_ALARM, the object uses alarm timer semantics and timer->timer is never initialized. Reusing that object from revision 0 causes mod_timer() on an uninitialized timer_list, triggering debugobjects warnings and possible panic when panic_on_warn=1.

Fix this by rejecting revision 0 rule insertion when an existing timer with the same label is of ALARM type.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23274"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-20T09:16:13Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels\n\nIDLETIMER revision 0 rules reuse existing timers by label and always call\nmod_timer() on timer-\u003etimer.\n\nIf the label was created first by revision 1 with XT_IDLETIMER_ALARM,\nthe object uses alarm timer semantics and timer-\u003etimer is never initialized.\nReusing that object from revision 0 causes mod_timer() on an uninitialized\ntimer_list, triggering debugobjects warnings and possible panic when\npanic_on_warn=1.\n\nFix this by rejecting revision 0 rule insertion when an existing timer with\nthe same label is of ALARM type.",
  "id": "GHSA-3cwp-73f3-j7w3",
  "modified": "2026-03-20T09:32:10Z",
  "published": "2026-03-20T09:32:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23274"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f228b9ae2a7e84d1153616d8e71c4236cb1f1309"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-23274 (GCVE-0-2026-23274)

Vulnerability from cvelistv5 – Published: 2026-03-20 08:08 – Updated: 2026-03-20 08:08

Title

netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels IDLETIMER revision 0 rules reuse existing timers by label and always call mod_timer() on timer->timer. If the label was created first by revision 1 with XT_IDLETIMER_ALARM, the object uses alarm timer semantics and timer->timer is never initialized. Reusing that object from revision 0 causes mod_timer() on an uninitialized timer_list, triggering debugobjects warnings and possible panic when panic_on_warn=1. Fix this by rejecting revision 0 rule insertion when an existing timer with the same label is of ALARM type.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/f5ef97c1316554248…
	https://git.kernel.org/stable/c/f228b9ae2a7e84d11…
	https://git.kernel.org/stable/c/329f0b9b48ee6ab59…

Impacted products

Vendor

Product

Version

Linux

Affected: 68983a354a655c35d3fb204489d383a2a051fda7 , < f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1 (git)
Affected: 68983a354a655c35d3fb204489d383a2a051fda7 , < f228b9ae2a7e84d1153616d8e71c4236cb1f1309 (git)
Affected: 68983a354a655c35d3fb204489d383a2a051fda7 , < 329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf (git)

Linux

Affected: 5.7
Unaffected: 0 , < 5.7 (semver)
Unaffected: 6.18.19 , ≤ 6.18.* (semver)
Unaffected: 6.19.9 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc4 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/xt_IDLETIMER.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1",
              "status": "affected",
              "version": "68983a354a655c35d3fb204489d383a2a051fda7",
              "versionType": "git"
            },
            {
              "lessThan": "f228b9ae2a7e84d1153616d8e71c4236cb1f1309",
              "status": "affected",
              "version": "68983a354a655c35d3fb204489d383a2a051fda7",
              "versionType": "git"
            },
            {
              "lessThan": "329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf",
              "status": "affected",
              "version": "68983a354a655c35d3fb204489d383a2a051fda7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/xt_IDLETIMER.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.19",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "5.7",
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                },
                {
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                  "versionEndExcluding": "7.0-rc4",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels\n\nIDLETIMER revision 0 rules reuse existing timers by label and always call\nmod_timer() on timer-\u003etimer.\n\nIf the label was created first by revision 1 with XT_IDLETIMER_ALARM,\nthe object uses alarm timer semantics and timer-\u003etimer is never initialized.\nReusing that object from revision 0 causes mod_timer() on an uninitialized\ntimer_list, triggering debugobjects warnings and possible panic when\npanic_on_warn=1.\n\nFix this by rejecting revision 0 rule insertion when an existing timer with\nthe same label is of ALARM type."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-20T08:08:54.918Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/f228b9ae2a7e84d1153616d8e71c4236cb1f1309"
        },
        {
          "url": "https://git.kernel.org/stable/c/329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf"
        }
      ],
      "title": "netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23274",
    "datePublished": "2026-03-20T08:08:54.918Z",
    "dateReserved": "2026-01-13T15:37:45.991Z",
    "dateUpdated": "2026-03-20T08:08:54.918Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-3CWP-73F3-J7W3

CVE-2026-23274 (GCVE-0-2026-23274)

Tags

Sightings

Nomenclature