{"id":"CVE-2026-52981","state":"PUBLISHED","title":"neigh: let neigh_xmit take skb ownership","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nneigh: let neigh_xmit take skb ownership\n\nneigh_xmit always releases the skb, except when no neighbour table is\nfound. But even the first added user of neigh_xmit (mpls) relied on\nneigh_xmit to release the skb (or queue it for tx).\n\nsashiko reported:\n If neigh_xmit() is called with an uninitialized neighbor table (for\n example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT\n and bypasses its internal out_kfree_skb error path.  Because the return\n value of neigh_xmit() is ignored here, does this leak the SKB?\n\nAssume full ownership and remove the last code path that doesn't\nxmit or free skb.","publishedAt":"2026-06-24T16:28:57.074Z","updatedAt":"2026-10-19T19:47:11.784Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"8a89054a1ec0767aec25ed2bbac933da6ba3cf5a","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"9247d59ca15bf60a57dca08103f055d8a4340877","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"0084712e0bee204b284510cdb63182fd5a30c2b7","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"63063ba60d2dc334e34f1e3f9271d7f3f6f30307","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"445e45a2c3a078316a62d2d331a570cf34ef5079","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"4438113be604ee67a7bf4f81da6e1cca41332ce4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/neighbour.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.1","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/neighbour.c"]}],"references":["https://git.kernel.org/stable/c/8a89054a1ec0767aec25ed2bbac933da6ba3cf5a","https://git.kernel.org/stable/c/9247d59ca15bf60a57dca08103f055d8a4340877","https://git.kernel.org/stable/c/0084712e0bee204b284510cdb63182fd5a30c2b7","https://git.kernel.org/stable/c/63063ba60d2dc334e34f1e3f9271d7f3f6f30307","https://git.kernel.org/stable/c/445e45a2c3a078316a62d2d331a570cf34ef5079","https://git.kernel.org/stable/c/4438113be604ee67a7bf4f81da6e1cca41332ce4"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/52xxx/CVE-2026-52981.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-52981","state":"PUBLISHED","datePublished":"2026-06-24T16:28:57.074Z","dateUpdated":"2026-10-19T19:47:11.784Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.376Z"},"containers":{"cna":{"title":"neigh: let neigh_xmit take skb ownership","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nneigh: let neigh_xmit take skb ownership\n\nneigh_xmit always releases the skb, except when no neighbour table is\nfound. But even the first added user of neigh_xmit (mpls) relied on\nneigh_xmit to release the skb (or queue it for tx).\n\nsashiko reported:\n If neigh_xmit() is called with an uninitialized neighbor table (for\n example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT\n and bypasses its internal out_kfree_skb error path.  Because the return\n value of neigh_xmit() is ignored here, does this leak the SKB?\n\nAssume full ownership and remove the last code path that doesn't\nxmit or free skb."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"8a89054a1ec0767aec25ed2bbac933da6ba3cf5a","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"9247d59ca15bf60a57dca08103f055d8a4340877","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"0084712e0bee204b284510cdb63182fd5a30c2b7","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"63063ba60d2dc334e34f1e3f9271d7f3f6f30307","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"445e45a2c3a078316a62d2d331a570cf34ef5079","versionType":"git"},{"version":"4fd3d7d9e868ffbdb0e7a67c5c8e9dfdcd846a62","status":"affected","lessThan":"4438113be604ee67a7bf4f81da6e1cca41332ce4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/neighbour.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.1","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/neighbour.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8a89054a1ec0767aec25ed2bbac933da6ba3cf5a"},{"url":"https://git.kernel.org/stable/c/9247d59ca15bf60a57dca08103f055d8a4340877"},{"url":"https://git.kernel.org/stable/c/0084712e0bee204b284510cdb63182fd5a30c2b7"},{"url":"https://git.kernel.org/stable/c/63063ba60d2dc334e34f1e3f9271d7f3f6f30307"},{"url":"https://git.kernel.org/stable/c/445e45a2c3a078316a62d2d331a570cf34ef5079"},{"url":"https://git.kernel.org/stable/c/4438113be604ee67a7bf4f81da6e1cca41332ce4"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - An unauthenticated packet sender can trigger the vulnerable `neigh_xmit()` path through configured network forwarding paths such as nftables netdev forwarding or MPLS forwarding. In the highest reasonable deployment, this is an exposed router/firewall datapath reachable by network traffic.\nAC:L - The bug is deterministic once the forwarding path uses a real neighbor table whose pointer is NULL, such as `NEIGH_ND_TABLE` when IPv6 neighbor discovery is unavailable. No race or heap shaping is required; repeated matching packets repeatedly leak skbs.\nPR:N - The attacker does not need privileges to send packets into an already configured vulnerable forwarding datapath. Although installing such rules/routes requires administrative network privileges, the packet-triggering attack itself is unauthenticated.\nUI:N - No victim user action is required after the affected forwarding configuration exists. The attacker only sends traffic that reaches the vulnerable path.\nS:U - The impact remains within the kernel/networking security authority of the affected system. There is no VM escape, sandbox boundary crossing, or separate security scope involved.\nC:N - The flaw is an skb memory leak caused by failing to free the packet buffer on the missing-table error path. It does not expose leaked memory contents to the attacker.\nI:N - The bug does not provide a memory corruption or data modification primitive. It only loses ownership of allocated skbs.\nA:H - An attacker can repeatedly trigger the leak with packets, consuming kernel memory and plausibly causing OOM, hangs, packet processing failure, or system-wide denial of service. Kernel memory exhaustion is a high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:32:19.237Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"6.6.141"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"6.12.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"6.18.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"7.0.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-52981","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:23:55.989578Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-401","lang":"en","type":"CWE","description":"CWE-401 Missing Release of Memory after Effective Lifetime"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:47:11.784Z"}}]}}}