{"api_version":"1","generated_at":"2026-09-20T21:39:46+00:00","cve":"CVE-2026-74742","urls":{"html":"https://cve.report/CVE-2026-74742","api":"https://cve.report/api/cve/CVE-2026-74742.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74742","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74742"},"summary":{"title":"veth: fix queue index used to wake the peer txq in veth_poll","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq->xdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv->rq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv->rq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-26 15:16:52","updated_at":"2026-08-27 06:17:23"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf","name":"https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23","name":"https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace","name":"https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7","name":"https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74742","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74742","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9fe31b3f314534e238aa6d0b6fb492134cbcf8be b662a1fb4f3a5ea19bac24eea8315b1d05be51e7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc82a33297fc2c58cb0b2b008d728668d45c0f6a 73f8dd22b1e533a99ecc3f9b5de6c6daccaecace git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc82a33297fc2c58cb0b2b008d728668d45c0f6a 90bb11fb29d3c55a2c46dc7c386d096b286e7fcf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc82a33297fc2c58cb0b2b008d728668d45c0f6a 60db47f02bfa2aa688938aa199117ec4f8e31d23 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.61 6.12.105 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.105 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.46 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.10 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74742","cve":"CVE-2026-74742","epss":"0.004660000","percentile":"0.384380000","score_date":"2026-08-27","updated_at":"2026-08-28 00:03:39"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/net/veth.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"b662a1fb4f3a5ea19bac24eea8315b1d05be51e7","status":"affected","version":"9fe31b3f314534e238aa6d0b6fb492134cbcf8be","versionType":"git"},{"lessThan":"73f8dd22b1e533a99ecc3f9b5de6c6daccaecace","status":"affected","version":"dc82a33297fc2c58cb0b2b008d728668d45c0f6a","versionType":"git"},{"lessThan":"90bb11fb29d3c55a2c46dc7c386d096b286e7fcf","status":"affected","version":"dc82a33297fc2c58cb0b2b008d728668d45c0f6a","versionType":"git"},{"lessThan":"60db47f02bfa2aa688938aa199117ec4f8e31d23","status":"affected","version":"dc82a33297fc2c58cb0b2b008d728668d45c0f6a","versionType":"git"},{"lessThan":"6.12.105","status":"affected","version":"6.12.61","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/net/veth.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.16"},{"lessThan":"6.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.105","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.46","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.105","versionStartIncluding":"6.12.61","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.46","versionStartIncluding":"6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.10","versionStartIncluding":"6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq->xdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv->rq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv->rq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing"}],"metrics":[{"cvssV3_1":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - Remote packets routed, NATed, or bridged into a suitably configured container veth reach veth_xmit() and veth_poll() through normal netdev transmit and NAPI softirq paths; no local syscall or physical access is required.\nAC:L - Sustained multi-flow traffic can deterministically fill the ptr_ring on a non-zero RX queue and drive its NAPI poller; waking queue 0 instead of the stopped queue is a logic bug, not a race or layout-dependent condition the attacker cannot control.\nPR:N - Multi-queue veth, GRO, and a non-noqueue qdisc are infrastructure prerequisites, not attacker privileges; forwarded packets traverse veth_xmit/veth_poll with no capability or authentication check, as with CVE-2025-68232 in the same backpressure code.\nUI:N - Exploitation requires only attacker-generated network traffic to drive backpressure on the veth pair; no victim action such as mounting filesystems or opening files is necessary.\nS:U - The defect leaves transmit queues in DRV_XOFF within the host kernel veth driver and does not cross VM, IOMMU, or sandbox security boundaries.\nC:N - The bug only mis-associates NAPI poll instances with peer TX queue indices during wakeup; there is no out-of-bounds access, use-after-free, or other memory read primitive.\nI:N - No memory corruption, arbitrary write, packet tampering, or control-flow influence occurs; the failure is limited to incorrect queue state management on the transmit path.\nA:H - When a non-zero peer TX queue is stopped for a full ptr_ring, veth_poll() never wakes it again and veth has no ndo_tx_timeout recovery, causing an indefinite transmit stall and persistent loss of connectivity on affected queues."}]}],"providerMetadata":{"dateUpdated":"2026-08-27T05:01:02.886Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7"},{"url":"https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace"},{"url":"https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf"},{"url":"https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23"}],"title":"veth: fix queue index used to wake the peer txq in veth_poll","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74742","datePublished":"2026-08-26T14:36:53.580Z","dateReserved":"2026-08-15T05:44:03.930Z","dateUpdated":"2026-08-27T05:01:02.886Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-26 15:16:52","lastModifiedDate":"2026-08-27 06:17:23","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74742","Ordinal":"1","Title":"veth: fix queue index used to wake the peer txq in veth_poll","CVE":"CVE-2026-74742","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74742","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq->xdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv->rq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv->rq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing","Type":"Description","Title":"veth: fix queue index used to wake the peer txq in veth_poll"}]}}}