{"id":"CVE-2026-46322","state":"PUBLISHED","title":"tun: free page on build_skb failure in tun_xdp_one()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntun: free page on build_skb failure in tun_xdp_one()\n\nWhen build_skb() fails in tun_xdp_one(), the function sets ret to\n-ENOMEM and jumps to the out label, which returns without freeing the\npage that vhost_net_build_xdp() allocated for the frame. As with the\nshort-frame rejection path, tun_sendmsg() discards the per-buffer error\nand still returns total_len, so vhost_tx_batch() takes the success path\nand never frees the page. Each build_skb() failure in a batch leaks one\npage-frag chunk.\n\nFree the page before taking the error path, matching the put_page() the\nother error exits of tun_xdp_one() already perform.","publishedAt":"2026-06-09T12:11:14.776Z","updatedAt":"2026-10-19T19:36:58.325Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"26fe549b5192536b6c1c68a2dfdc8c0dcf9fa4a9","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"793385c154771603b8671dd8338927221e9d8d78","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"2638a9c1521905bb5c5d1e95c8fbc09f79148ed7","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"60d9c0d6cdde5420d6483c921b16fe5465eb5238","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"d16e38fac09a47bfcf98c1ad65a1bb53f94540f5","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"aa308e9dbb9acb17cacdbbce9e4504f69bac8385","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"4fefc6156a162a9f50035c12091a5e5130c82c6e","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"aa8963fdce667a42fb7f0bdd2909fadcab02f9a8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tun.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","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":["drivers/net/tun.c"]}],"references":["https://git.kernel.org/stable/c/26fe549b5192536b6c1c68a2dfdc8c0dcf9fa4a9","https://git.kernel.org/stable/c/793385c154771603b8671dd8338927221e9d8d78","https://git.kernel.org/stable/c/2638a9c1521905bb5c5d1e95c8fbc09f79148ed7","https://git.kernel.org/stable/c/60d9c0d6cdde5420d6483c921b16fe5465eb5238","https://git.kernel.org/stable/c/d16e38fac09a47bfcf98c1ad65a1bb53f94540f5","https://git.kernel.org/stable/c/aa308e9dbb9acb17cacdbbce9e4504f69bac8385","https://git.kernel.org/stable/c/4fefc6156a162a9f50035c12091a5e5130c82c6e","https://git.kernel.org/stable/c/aa8963fdce667a42fb7f0bdd2909fadcab02f9a8","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46322.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46322","state":"PUBLISHED","datePublished":"2026-06-09T12:11:14.776Z","dateUpdated":"2026-10-19T19:36:58.325Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.112Z"},"containers":{"cna":{"title":"tun: free page on build_skb failure in tun_xdp_one()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntun: free page on build_skb failure in tun_xdp_one()\n\nWhen build_skb() fails in tun_xdp_one(), the function sets ret to\n-ENOMEM and jumps to the out label, which returns without freeing the\npage that vhost_net_build_xdp() allocated for the frame. As with the\nshort-frame rejection path, tun_sendmsg() discards the per-buffer error\nand still returns total_len, so vhost_tx_batch() takes the success path\nand never frees the page. Each build_skb() failure in a batch leaks one\npage-frag chunk.\n\nFree the page before taking the error path, matching the put_page() the\nother error exits of tun_xdp_one() already perform."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"26fe549b5192536b6c1c68a2dfdc8c0dcf9fa4a9","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"793385c154771603b8671dd8338927221e9d8d78","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"2638a9c1521905bb5c5d1e95c8fbc09f79148ed7","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"60d9c0d6cdde5420d6483c921b16fe5465eb5238","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"d16e38fac09a47bfcf98c1ad65a1bb53f94540f5","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"aa308e9dbb9acb17cacdbbce9e4504f69bac8385","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"4fefc6156a162a9f50035c12091a5e5130c82c6e","versionType":"git"},{"version":"043d222f93ab8c76b56a3b315cd8692e35affb6c","status":"affected","lessThan":"aa8963fdce667a42fb7f0bdd2909fadcab02f9a8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tun.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.35","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.12","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":["drivers/net/tun.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/26fe549b5192536b6c1c68a2dfdc8c0dcf9fa4a9"},{"url":"https://git.kernel.org/stable/c/793385c154771603b8671dd8338927221e9d8d78"},{"url":"https://git.kernel.org/stable/c/2638a9c1521905bb5c5d1e95c8fbc09f79148ed7"},{"url":"https://git.kernel.org/stable/c/60d9c0d6cdde5420d6483c921b16fe5465eb5238"},{"url":"https://git.kernel.org/stable/c/d16e38fac09a47bfcf98c1ad65a1bb53f94540f5"},{"url":"https://git.kernel.org/stable/c/aa308e9dbb9acb17cacdbbce9e4504f69bac8385"},{"url":"https://git.kernel.org/stable/c/4fefc6156a162a9f50035c12091a5e5130c82c6e"},{"url":"https://git.kernel.org/stable/c/aa8963fdce667a42fb7f0bdd2909fadcab02f9a8"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through the TUN `sendmsg()` path with `TUN_MSG_PTR`, which in production is driven by host `vhost-net` processing virtio-net TX descriptors from a VM guest or a local process holding a TUN/vhost-net fd—not by the host parsing remote network packets.\nAC:L - An attacker can reliably trigger `build_skb()` failure by first pressuring the `sk_buff` slab (e.g., flooding virtio TX or other allocations) and then sending batched virtio TX frames; they control both the memory-pressure side and the batch submission side.\nPR:N - In the highest-impact scenario—a malicious tenant in a cloud/KVM guest with virtio-net and vhost-net—the attacker needs no host privileges; any guest process that can transmit on the virtio TX queue can drive this path.\nUI:N - Exploitation requires no victim interaction beyond normal VM networking; the guest attacker can trigger the leak programmatically without the host user performing any action.\nS:C - The leak consumes host kernel memory from a guest VM security context, crossing the VM/host boundary and impacting resources outside the attacker's guest security authority.\nC:N - This is a pure page reference leak with no out-of-bounds access, use-after-free, or attacker-readable disclosure; leaked pages remain in the kernel allocator and are not exposed to the attacker.\nI:N - No memory corruption, arbitrary write, or control-flow hijack occurs; the only defect is failing to `put_page()` on the `build_skb()` error path.\nA:H - Each failed `build_skb()` leaks a page-frag (~4 KiB), batches can hold up to 64 XDP buffers, and `tun_sendmsg()` masks per-buffer errors so leaks are unbounded and repeatable, enabling sustained host kernel memory exhaustion and OOM/DoS."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:31:17.322Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.0.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:21:37.036Z"},"x_adpType":"supplier"},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-46322","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:22:05.058396Z"}}}],"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":"2026-10-19T19:36:58.325Z"}}]}}}