{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-52919", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.367Z", "datePublished": "2026-06-24T07:14:15.201Z", "dateUpdated": "2026-08-05T12:31:41.245Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:31:41.245Z" }, "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": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "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's 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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/batman-adv/tp_meter.c" ], "versions": [ { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "e75e2ab463b5b34df6b98f94d740aff327ce9f6b", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "abae88fa254f2981d39ac003a7b302528a22af64", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "c66d20a3ff095e3f000551d208ec2606616db15c", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "c1bac194733aabd731aafa6a01350c229e187dba", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "01cefc5923889e29dbb5f281c3d457714ceb9c00", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "90ae3eae06b7b8ab9f6250b9497c860915b4c17b", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "aeae11c5dad9cd0d50723890bdd866f8e6db2e7d", "status": "affected", "versionType": "git" }, { "version": "33a3bb4a3345bb511f9c69c913da95d4693e2a4e", "lessThan": "94f3b133168d1c49895e7cc6afbcf1cc0b354602", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/batman-adv/tp_meter.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.1" } ] } ] } ], "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" } } } }