CVE-2026-43374 (GCVE-0-2026-43374)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-05-08 14:21
VLAI?
Title
net: nexthop: fix percpu use-after-free in remove_nh_grp_entry
Summary
In the Linux kernel, the following vulnerability has been resolved: net: nexthop: fix percpu use-after-free in remove_nh_grp_entry When removing a nexthop from a group, remove_nh_grp_entry() publishes the new group via rcu_assign_pointer() then immediately frees the removed entry's percpu stats with free_percpu(). However, the synchronize_net() grace period in the caller remove_nexthop_from_groups() runs after the free. RCU readers that entered before the publish still see the old group and can dereference the freed stats via nh_grp_entry_stats_inc() -> get_cpu_ptr(nhge->stats), causing a use-after-free on percpu memory. Fix by deferring the free_percpu() until after synchronize_net() in the caller. Removed entries are chained via nh_list onto a local deferred free list. After the grace period completes and all RCU readers have finished, the percpu stats are safely freed.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: f4676ea74b8549cd88dbfe2a592ce4530039e61f , < abf4feaee6405f1441929c6ebe7a250f2cd170a7 (git)
Affected: f4676ea74b8549cd88dbfe2a592ce4530039e61f , < ab5ebab9664214ba41a7633cb4e72f128204f924 (git)
Affected: f4676ea74b8549cd88dbfe2a592ce4530039e61f , < 9e08ad731862b22a87cc55f752e16d66cdc9e231 (git)
Affected: f4676ea74b8549cd88dbfe2a592ce4530039e61f , < b2662e7593e94ae09b1cf7ee5f09160a3612bcb2 (git)
Create a notification for this product.
    Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.19 , ≤ 6.18.* (semver)
Unaffected: 6.19.9 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/nexthop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "abf4feaee6405f1441929c6ebe7a250f2cd170a7",
              "status": "affected",
              "version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
              "versionType": "git"
            },
            {
              "lessThan": "ab5ebab9664214ba41a7633cb4e72f128204f924",
              "status": "affected",
              "version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
              "versionType": "git"
            },
            {
              "lessThan": "9e08ad731862b22a87cc55f752e16d66cdc9e231",
              "status": "affected",
              "version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
              "versionType": "git"
            },
            {
              "lessThan": "b2662e7593e94ae09b1cf7ee5f09160a3612bcb2",
              "status": "affected",
              "version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/nexthop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.78",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.19",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.9",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nexthop: fix percpu use-after-free in remove_nh_grp_entry\n\nWhen removing a nexthop from a group, remove_nh_grp_entry() publishes\nthe new group via rcu_assign_pointer() then immediately frees the\nremoved entry\u0027s percpu stats with free_percpu(). However, the\nsynchronize_net() grace period in the caller remove_nexthop_from_groups()\nruns after the free. RCU readers that entered before the publish still\nsee the old group and can dereference the freed stats via\nnh_grp_entry_stats_inc() -\u003e get_cpu_ptr(nhge-\u003estats), causing a\nuse-after-free on percpu memory.\n\nFix by deferring the free_percpu() until after synchronize_net() in the\ncaller. Removed entries are chained via nh_list onto a local deferred\nfree list. After the grace period completes and all RCU readers have\nfinished, the percpu stats are safely freed."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-08T14:21:24.537Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/abf4feaee6405f1441929c6ebe7a250f2cd170a7"
        },
        {
          "url": "https://git.kernel.org/stable/c/ab5ebab9664214ba41a7633cb4e72f128204f924"
        },
        {
          "url": "https://git.kernel.org/stable/c/9e08ad731862b22a87cc55f752e16d66cdc9e231"
        },
        {
          "url": "https://git.kernel.org/stable/c/b2662e7593e94ae09b1cf7ee5f09160a3612bcb2"
        }
      ],
      "title": "net: nexthop: fix percpu use-after-free in remove_nh_grp_entry",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43374",
    "datePublished": "2026-05-08T14:21:24.537Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
    "dateUpdated": "2026-05-08T14:21:24.537Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43374",
      "date": "2026-05-09",
      "epss": "0.00018",
      "percentile": "0.04722"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43374\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-08T15:16:48.547\",\"lastModified\":\"2026-05-08T15:16:48.547\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: nexthop: fix percpu use-after-free in remove_nh_grp_entry\\n\\nWhen removing a nexthop from a group, remove_nh_grp_entry() publishes\\nthe new group via rcu_assign_pointer() then immediately frees the\\nremoved entry\u0027s percpu stats with free_percpu(). However, the\\nsynchronize_net() grace period in the caller remove_nexthop_from_groups()\\nruns after the free. RCU readers that entered before the publish still\\nsee the old group and can dereference the freed stats via\\nnh_grp_entry_stats_inc() -\u003e get_cpu_ptr(nhge-\u003estats), causing a\\nuse-after-free on percpu memory.\\n\\nFix by deferring the free_percpu() until after synchronize_net() in the\\ncaller. Removed entries are chained via nh_list onto a local deferred\\nfree list. After the grace period completes and all RCU readers have\\nfinished, the percpu stats are safely freed.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/9e08ad731862b22a87cc55f752e16d66cdc9e231\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ab5ebab9664214ba41a7633cb4e72f128204f924\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/abf4feaee6405f1441929c6ebe7a250f2cd170a7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b2662e7593e94ae09b1cf7ee5f09160a3612bcb2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.