{"id":"CVE-2026-46321","state":"PUBLISHED","title":"tun: free page on short-frame rejection in tun_xdp_one()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntun: free page on short-frame rejection in tun_xdp_one()\n\ntun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without\nfreeing the page that vhost_net_build_xdp() allocated for it.\ntun_sendmsg() discards that -EINVAL and still returns total_len, so\nvhost_tx_batch() takes the success path and never frees the page; each\nshort frame in a batch leaks one page-frag chunk.\n\nA local process that can open /dev/net/tun and /dev/vhost-net can hit\nthis path: it attaches a tun/tap device as the vhost-net backend and\nfeeds TX descriptors whose length minus the virtio-net header is below\nETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a\ntight submission loop exhausts host memory and triggers an OOM panic.\nFree the page before returning -EINVAL, matching the XDP-program error\npath in the same function.","publishedAt":"2026-06-09T12:11:13.872Z","updatedAt":"2026-10-15T01:21:35.519Z","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":"6100e0237204890269e3f934acfc50d35fd6f319","status":"affected","lessThan":"0a6f46a9332ad6958992d64d3b3a81a80b2ca940","versionType":"git"},{"version":"589382f50b4a5d90d16d8bc9dcbc0e927a3e39b2","status":"affected","lessThan":"0e8211fcf9426f5adddf32516ba0f400ceb9544d","versionType":"git"},{"version":"ad6b3f622ccfb4bfedfa53b6ebd91c3d1d04f146","status":"affected","lessThan":"e915445942af6dcea628bf66d6241641201a0c41","versionType":"git"},{"version":"d5ad89b7d01ed4e66fd04734fc63d6e78536692a","status":"affected","lessThan":"5b34f9e4fe2f203724a6e893d6df0316b9670057","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"69863ff2720a0e9871f1a5710f2a33a94217fee0","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"37a1c268c2c8090bf4dc552d732bd23ba36f8eb0","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"98c67be9eb9de72465a071949e84a3cdb8fab5a3","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"f4feb1e20058e407cb00f45aff47f5b7e19a6bbf","versionType":"git"},{"version":"32b0aaba5dbc85816898167d9b5d45a22eae82e9","status":"affected","versionType":"git"},{"version":"a9d1c27e2ee3b0ea5d40c105d6e728fc114470bb","status":"affected","versionType":"git"},{"version":"8418f55302fa1d2eeb73e16e345167e545c598a5","status":"affected","versionType":"git"},{"version":"5.10.223","status":"affected","lessThan":"5.10.259","versionType":"semver"},{"version":"5.15.164","status":"affected","lessThan":"5.15.210","versionType":"semver"},{"version":"6.1.102","status":"affected","lessThan":"6.1.176","versionType":"semver"},{"version":"6.6.43","status":"affected","lessThan":"6.6.143","versionType":"semver"},{"version":"5.4.281","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"6.9.12","status":"affected","lessThan":"6.10","versionType":"semver"},{"version":"6.10.2","status":"affected","lessThan":"6.11","versionType":"semver"}],"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":"6.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.11","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/0a6f46a9332ad6958992d64d3b3a81a80b2ca940","https://git.kernel.org/stable/c/0e8211fcf9426f5adddf32516ba0f400ceb9544d","https://git.kernel.org/stable/c/e915445942af6dcea628bf66d6241641201a0c41","https://git.kernel.org/stable/c/5b34f9e4fe2f203724a6e893d6df0316b9670057","https://git.kernel.org/stable/c/69863ff2720a0e9871f1a5710f2a33a94217fee0","https://git.kernel.org/stable/c/37a1c268c2c8090bf4dc552d732bd23ba36f8eb0","https://git.kernel.org/stable/c/98c67be9eb9de72465a071949e84a3cdb8fab5a3","https://git.kernel.org/stable/c/f4feb1e20058e407cb00f45aff47f5b7e19a6bbf","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46321.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46321","state":"PUBLISHED","datePublished":"2026-06-09T12:11:13.872Z","dateUpdated":"2026-10-15T01:21:35.519Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.112Z"},"containers":{"cna":{"title":"tun: free page on short-frame rejection in tun_xdp_one()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntun: free page on short-frame rejection in tun_xdp_one()\n\ntun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without\nfreeing the page that vhost_net_build_xdp() allocated for it.\ntun_sendmsg() discards that -EINVAL and still returns total_len, so\nvhost_tx_batch() takes the success path and never frees the page; each\nshort frame in a batch leaks one page-frag chunk.\n\nA local process that can open /dev/net/tun and /dev/vhost-net can hit\nthis path: it attaches a tun/tap device as the vhost-net backend and\nfeeds TX descriptors whose length minus the virtio-net header is below\nETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a\ntight submission loop exhausts host memory and triggers an OOM panic.\nFree the page before returning -EINVAL, matching the XDP-program error\npath in the same function."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6100e0237204890269e3f934acfc50d35fd6f319","status":"affected","lessThan":"0a6f46a9332ad6958992d64d3b3a81a80b2ca940","versionType":"git"},{"version":"589382f50b4a5d90d16d8bc9dcbc0e927a3e39b2","status":"affected","lessThan":"0e8211fcf9426f5adddf32516ba0f400ceb9544d","versionType":"git"},{"version":"ad6b3f622ccfb4bfedfa53b6ebd91c3d1d04f146","status":"affected","lessThan":"e915445942af6dcea628bf66d6241641201a0c41","versionType":"git"},{"version":"d5ad89b7d01ed4e66fd04734fc63d6e78536692a","status":"affected","lessThan":"5b34f9e4fe2f203724a6e893d6df0316b9670057","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"69863ff2720a0e9871f1a5710f2a33a94217fee0","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"37a1c268c2c8090bf4dc552d732bd23ba36f8eb0","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"98c67be9eb9de72465a071949e84a3cdb8fab5a3","versionType":"git"},{"version":"049584807f1d797fc3078b68035450a9769eb5c3","status":"affected","lessThan":"f4feb1e20058e407cb00f45aff47f5b7e19a6bbf","versionType":"git"},{"version":"32b0aaba5dbc85816898167d9b5d45a22eae82e9","status":"affected","versionType":"git"},{"version":"a9d1c27e2ee3b0ea5d40c105d6e728fc114470bb","status":"affected","versionType":"git"},{"version":"8418f55302fa1d2eeb73e16e345167e545c598a5","status":"affected","versionType":"git"},{"version":"5.10.223","status":"affected","lessThan":"5.10.259","versionType":"semver"},{"version":"5.15.164","status":"affected","lessThan":"5.15.210","versionType":"semver"},{"version":"6.1.102","status":"affected","lessThan":"6.1.176","versionType":"semver"},{"version":"6.6.43","status":"affected","lessThan":"6.6.143","versionType":"semver"},{"version":"5.4.281","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"6.9.12","status":"affected","lessThan":"6.10","versionType":"semver"},{"version":"6.10.2","status":"affected","lessThan":"6.11","versionType":"semver"}],"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":"6.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.11","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/0a6f46a9332ad6958992d64d3b3a81a80b2ca940"},{"url":"https://git.kernel.org/stable/c/0e8211fcf9426f5adddf32516ba0f400ceb9544d"},{"url":"https://git.kernel.org/stable/c/e915445942af6dcea628bf66d6241641201a0c41"},{"url":"https://git.kernel.org/stable/c/5b34f9e4fe2f203724a6e893d6df0316b9670057"},{"url":"https://git.kernel.org/stable/c/69863ff2720a0e9871f1a5710f2a33a94217fee0"},{"url":"https://git.kernel.org/stable/c/37a1c268c2c8090bf4dc552d732bd23ba36f8eb0"},{"url":"https://git.kernel.org/stable/c/98c67be9eb9de72465a071949e84a3cdb8fab5a3"},{"url":"https://git.kernel.org/stable/c/f4feb1e20058e407cb00f45aff47f5b7e19a6bbf"}],"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 flaw is reached via local host interfaces (/dev/net/tun and /dev/vhost-net ioctls/sendmsg) or from a KVM guest through virtio-net TX descriptors processed by vhost-net, not via remote network packets to the host stack.\nAC:L - An attacker reliably triggers the leak by repeatedly submitting TX frames whose length minus the virtio-net header is below ETH_HLEN; no races or attacker-uncontrollable layout conditions are required.\nPR:N - A malicious KVM guest on a host using vhost-net with a tun/tap backend needs no host privileges—only the ability to craft short virtio-net TX descriptors—while a direct host attacker can also obtain CAP_NET_ADMIN via unprivileged user namespaces.\nUI:N - Exploitation requires no victim interaction beyond normal VM or namespace operation; the attacker drives the vhost TX path directly in a tight loop.\nS:C - In the highest-impact cloud/KVM deployment, an unprivileged guest VM crosses the hypervisor security boundary to exhaust host kernel memory and panic the host, affecting resources outside the guest's security scope.\nC:N - The bug is a page-fragment memory leak with no out-of-bounds access, use-after-free, or information disclosure; freed pages are simply never returned to the allocator.\nI:N - No kernel memory corruption or data modification occurs; the only effect is unbounded consumption of page-frags leading to denial of service.\nA:H - Sustained submission of short batched frames leaks one page-frag per frame, exhausts host memory, and can trigger an OOM kernel panic as described in the fix commit."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:31:16.239Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.223","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.164","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.102","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.43","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"7.0.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11","versionEndExcluding":"7.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.281"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10.2"}]}]}],"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":"2026-10-15T01:21:35.519Z"},"x_adpType":"supplier"}]}}}