{"api_version":"1","generated_at":"2026-10-21T18:43:04+00:00","cve":"CVE-2026-98556","urls":{"html":"https://cve.report/CVE-2026-98556","api":"https://cve.report/api/cve/CVE-2026-98556.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98556","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98556"},"summary":{"title":"gve: DQO: reject TSO packets with an out of range MSS","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ngve: DQO: reject TSO packets with an out of range MSS\n\ngve_prep_tso() notes that the device requires the MSS to be <= 9728,\nbut does not enforce it, assuming the 9K MTU enforced by the hypervisor\nand the 64KB limit on TSO sizes are enough.\n\nThis does not hold for packets that were not generated locally.\nA guest behind a tap, or any packet socket user, can provide an\narbitrary gso_size in virtio_net_hdr. Layer 2 forwarding does not check\nthe MTU for GSO packets (is_skb_forwardable()), and gso_features_check()\nonly bounds skb->len and gso_segs, never gso_size.\n\nSuch a packet reaches gve_tx_fill_tso_ctx_desc(), which puts gso_size\ninto the mss field of the TSO context descriptor. This field is 14 bits\nwide, so a gso_size of 16384 is silently turned into an MSS of zero.\n\nDrop these packets from gve_prep_tso(), and make sure that\ngve_features_check_dqo() leaves their GSO bits alone: skb_segment()\nsplits at gso_size regardless of the MTU, so falling back to software\nsegmentation would give the device non TSO packets bigger than the\n9728 bytes it supports.\n\nNote that the device can still be given oversized non TSO packets when\nthe stack segments in software for other reasons, for instance after\nTSO has been disabled with ethtool. This is a generic issue, because\nthe MTU check is skipped for GSO packets in the forwarding path, and\nis addressed separately.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:17:07","updated_at":"2026-10-18 16:17:07"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/c517e8755960c8c6335ebf7dae6c95c43e5fb085","name":"https://git.kernel.org/stable/c/c517e8755960c8c6335ebf7dae6c95c43e5fb085","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2dc3ae3942e151fef254b7bbb65c832192ad2069","name":"https://git.kernel.org/stable/c/2dc3ae3942e151fef254b7bbb65c832192ad2069","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/296c83b5ccc808c080865eb20fd7a477b0355bb7","name":"https://git.kernel.org/stable/c/296c83b5ccc808c080865eb20fd7a477b0355bb7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98556","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98556","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a57e5de476be0b4b7f42beb6a21c19ad9c577aa3 2dc3ae3942e151fef254b7bbb65c832192ad2069 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a57e5de476be0b4b7f42beb6a21c19ad9c577aa3 c517e8755960c8c6335ebf7dae6c95c43e5fb085 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a57e5de476be0b4b7f42beb6a21c19ad9c577aa3 296c83b5ccc808c080865eb20fd7a477b0355bb7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.55 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.9 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc5 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/net/ethernet/google/gve/gve_desc_dqo.h","drivers/net/ethernet/google/gve/gve_tx_dqo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2dc3ae3942e151fef254b7bbb65c832192ad2069","status":"affected","version":"a57e5de476be0b4b7f42beb6a21c19ad9c577aa3","versionType":"git"},{"lessThan":"c517e8755960c8c6335ebf7dae6c95c43e5fb085","status":"affected","version":"a57e5de476be0b4b7f42beb6a21c19ad9c577aa3","versionType":"git"},{"lessThan":"296c83b5ccc808c080865eb20fd7a477b0355bb7","status":"affected","version":"a57e5de476be0b4b7f42beb6a21c19ad9c577aa3","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/net/ethernet/google/gve/gve_desc_dqo.h","drivers/net/ethernet/google/gve/gve_tx_dqo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.14"},{"lessThan":"5.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.55","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc5","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.55","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.9","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc5","versionStartIncluding":"5.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ngve: DQO: reject TSO packets with an out of range MSS\n\ngve_prep_tso() notes that the device requires the MSS to be <= 9728,\nbut does not enforce it, assuming the 9K MTU enforced by the hypervisor\nand the 64KB limit on TSO sizes are enough.\n\nThis does not hold for packets that were not generated locally.\nA guest behind a tap, or any packet socket user, can provide an\narbitrary gso_size in virtio_net_hdr. Layer 2 forwarding does not check\nthe MTU for GSO packets (is_skb_forwardable()), and gso_features_check()\nonly bounds skb->len and gso_segs, never gso_size.\n\nSuch a packet reaches gve_tx_fill_tso_ctx_desc(), which puts gso_size\ninto the mss field of the TSO context descriptor. This field is 14 bits\nwide, so a gso_size of 16384 is silently turned into an MSS of zero.\n\nDrop these packets from gve_prep_tso(), and make sure that\ngve_features_check_dqo() leaves their GSO bits alone: skb_segment()\nsplits at gso_size regardless of the MTU, so falling back to software\nsegmentation would give the device non TSO packets bigger than the\n9728 bytes it supports.\n\nNote that the device can still be given oversized non TSO packets when\nthe stack segments in software for other reasons, for instance after\nTSO has been disabled with ethtool. This is a generic issue, because\nthe MTU check is skipped for GSO packets in the forwarding path, and\nis addressed separately."}],"providerMetadata":{"dateUpdated":"2026-10-18T15:18:23.536Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2dc3ae3942e151fef254b7bbb65c832192ad2069"},{"url":"https://git.kernel.org/stable/c/c517e8755960c8c6335ebf7dae6c95c43e5fb085"},{"url":"https://git.kernel.org/stable/c/296c83b5ccc808c080865eb20fd7a477b0355bb7"}],"title":"gve: DQO: reject TSO packets with an out of range MSS","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98556","datePublished":"2026-10-18T15:18:23.536Z","dateReserved":"2026-09-25T10:25:14.357Z","dateUpdated":"2026-10-18T15:18:23.536Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:17:07","lastModifiedDate":"2026-10-18 16:17:07","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98556","Ordinal":"1","Title":"gve: DQO: reject TSO packets with an out of range MSS","CVE":"CVE-2026-98556","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98556","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\ngve: DQO: reject TSO packets with an out of range MSS\n\ngve_prep_tso() notes that the device requires the MSS to be <= 9728,\nbut does not enforce it, assuming the 9K MTU enforced by the hypervisor\nand the 64KB limit on TSO sizes are enough.\n\nThis does not hold for packets that were not generated locally.\nA guest behind a tap, or any packet socket user, can provide an\narbitrary gso_size in virtio_net_hdr. Layer 2 forwarding does not check\nthe MTU for GSO packets (is_skb_forwardable()), and gso_features_check()\nonly bounds skb->len and gso_segs, never gso_size.\n\nSuch a packet reaches gve_tx_fill_tso_ctx_desc(), which puts gso_size\ninto the mss field of the TSO context descriptor. This field is 14 bits\nwide, so a gso_size of 16384 is silently turned into an MSS of zero.\n\nDrop these packets from gve_prep_tso(), and make sure that\ngve_features_check_dqo() leaves their GSO bits alone: skb_segment()\nsplits at gso_size regardless of the MTU, so falling back to software\nsegmentation would give the device non TSO packets bigger than the\n9728 bytes it supports.\n\nNote that the device can still be given oversized non TSO packets when\nthe stack segments in software for other reasons, for instance after\nTSO has been disabled with ethtool. This is a generic issue, because\nthe MTU check is skipped for GSO packets in the forwarding path, and\nis addressed separately.","Type":"Description","Title":"gve: DQO: reject TSO packets with an out of range MSS"}]}}}