CVE-2026-52919 (GCVE-0-2026-52919)
Vulnerability from cvelistv5
Published
2026-06-24 07:14
Modified
2026-08-05 12:31
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix tp_meter counter underflow during shutdown batadv_tp_sender_shutdown() unconditionally decrements the "sending" atomic counter. If multiple paths (e.g. timeout, user cancel, and normal finish) call this function, the counter can underflow to -1. Since the sender logic treats any non-zero value as "still sending", a negative value causes the sender kthread to loop indefinitely. This leads to a use-after-free when the interface is removed while the zombie thread is still active. Fix this by using atomic_xchg() to ensure the counter only transitions from 1 to 0 once. [sven: added missing change in batadv_tp_send]
References
Impacted products
Vendor Product Version
Linux Linux Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
Version: 33a3bb4a3345bb511f9c69c913da95d4693e2a4e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/batman-adv/tp_meter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "4.8"
            },
            {
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              "status": "unaffected",
              "version": "0",
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            },
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              "status": "unaffected",
              "version": "5.10.258",
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            {
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              "version": "5.15.209",
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            {
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              "status": "unaffected",
              "version": "6.1.175",
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              "status": "unaffected",
              "version": "6.6.142",
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
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            },
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              "status": "unaffected",
              "version": "6.18.34",
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              "status": "unaffected",
              "version": "7.0.11",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
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                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
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                {
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                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.142",
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                {
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                  "versionStartIncluding": "4.8",
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                  "vulnerable": true
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                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: fix tp_meter counter underflow during shutdown\n\nbatadv_tp_sender_shutdown() unconditionally decrements the \"sending\"\natomic counter. If multiple paths (e.g. timeout, user cancel, and\nnormal finish) call this function, the counter can underflow to -1.\n\nSince the sender logic treats any non-zero value as \"still sending\",\na negative value causes the sender kthread to loop indefinitely.\nThis leads to a use-after-free when the interface is removed while\nthe zombie thread is still active.\n\nFix this by using atomic_xchg() to ensure the counter only transitions\nfrom 1 to 0 once.\n\n[sven: added missing change in batadv_tp_send]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable sender shutdown path is reached through the batman-adv generic netlink tp_meter start/cancel operations and mesh-interface teardown, which are local kernel control interfaces rather than packets alone. Adjacent mesh packets can influence timing, but an attacker must be able to initiate or cancel the tp_meter session locally to reliably hit the underflow.\nAC:L - The underflow occurs when multiple attacker-controllable stop paths act on the same session, such as a short test/timeout plus cancel or teardown. Although timing is involved, the attacker controls the session lifetime and can repeat the race, so this is low complexity.\nPR:L - The tp_meter genl commands use GENL_UNS_ADMIN_PERM, requiring CAP_NET_ADMIN in the caller\u0027s user namespace. Because batman-adv is netns-aware and can be driven from user namespaces when available, this is low rather than high privilege.\nUI:N - A local attacker with the required namespace capability can create/start/cancel/tear down the tp_meter session without any separate victim action. No user needs to open a file, mount anything, or interact with attacker-controlled data.\nS:U - The bug corrupts/uses kernel networking subsystem state within the same kernel security authority. It is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The fix commit states the negative sender counter leaves a zombie kthread active and leads to a use-after-free during interface removal. Per kernel scoring guidance, a kernel UAF is treated as potentially enabling high confidentiality impact.\nI:H - The resulting use-after-free is kernel memory corruption and can plausibly be shaped into write/control-flow primitives in the most severe reasonable scenario. Per guidance, kernel UAFs are scored as high integrity impact.\nA:H - At minimum, the negative counter can keep the sender kthread looping indefinitely and hang teardown; the documented UAF can also crash the kernel. This is high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:31:41.245Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e75e2ab463b5b34df6b98f94d740aff327ce9f6b"
        },
        {
          "url": "https://git.kernel.org/stable/c/abae88fa254f2981d39ac003a7b302528a22af64"
        },
        {
          "url": "https://git.kernel.org/stable/c/c66d20a3ff095e3f000551d208ec2606616db15c"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1bac194733aabd731aafa6a01350c229e187dba"
        },
        {
          "url": "https://git.kernel.org/stable/c/01cefc5923889e29dbb5f281c3d457714ceb9c00"
        },
        {
          "url": "https://git.kernel.org/stable/c/90ae3eae06b7b8ab9f6250b9497c860915b4c17b"
        },
        {
          "url": "https://git.kernel.org/stable/c/aeae11c5dad9cd0d50723890bdd866f8e6db2e7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/94f3b133168d1c49895e7cc6afbcf1cc0b354602"
        }
      ],
      "title": "batman-adv: fix tp_meter counter underflow during shutdown",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52919",
    "datePublished": "2026-06-24T07:14:15.201Z",
    "dateReserved": "2026-06-09T07:44:35.367Z",
    "dateUpdated": "2026-08-05T12:31:41.245Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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