{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80725", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.789Z", "datePublished": "2026-08-29T06:39:35.212Z", "dateUpdated": "2026-08-29T06:40:30.300Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-29T06:40:30.300Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: gro: properly validate BIG TCP aggregation criteria\n\nWhen GRO attempts to aggregate packets beyond GRO_LEGACY_MAX_SIZE (64KB),\nBIG TCP should only be permitted for plain IPv4 TCP and plain IPv6 TCP\n(with sufficient MAC header room to insert the temporary HBH jumbo header).\n\nHowever, commit b1a78b9b9886 (\"net: add support for ipv4 big tcp\")\nloosened the check in skb_gro_receive(), leading to several issues:\n\n1. skb_gro_receive() checked skb_headroom(p) instead of the actual space\n before the MAC header (p->mac_header). Because skb_headroom(p) includes\n mac_len, crafted frames (e.g. injected via AF_PACKET) can pass the check\n with p->mac_header < 8 bytes. When ipv6_gro_complete() inserts the\n temporary HBH jumbo header, the memmove() starts before skb->head,\n causing an out-of-bounds write and wrapping skb->mac_header.\n2. It allowed non-IP protocols such as software VLAN (ETH_P_8021Q /\n ETH_P_8021AD) to aggregate beyond 64KB because\n p->protocol != ETH_P_IPV6 was true.\n3. It checked p->encapsulation instead of NAPI_GRO_CB(skb)->encap_mark,\n allowing encapsulated flows (e.g. SIT / IPv6-in-IPv4) to aggregate\n beyond 64KB.\n\nFix skb_gro_receive() to strictly enforce:\n- NAPI_GRO_CB(skb)->proto == IPPROTO_TCP\n- Not encapsulated (!NAPI_GRO_CB(skb)->encap_mark && !p->encapsulation)\n- Protocol must be either ETH_P_IP or ETH_P_IPV6\n- If ETH_P_IPV6, p->mac_header must be at least\n sizeof(struct hop_jumbo_hdr)\n\nReturning -E2BIG from skb_gro_receive() ensures that packets which cannot\nbecome BIG TCP are cleanly flushed at <= 64KB and delivered intact without\ndropping.\n\nThis issue does not exist in mainline (7.0+) because the subsystem was\nrewritten in commit 81be30c1f5f2 (\"net/ipv6: Drop HBH for BIG TCP on RX\nside\"), making this fix relevant only for older stable branches like\n6.18.y." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/gro.c" ], "versions": [ { "version": "0fe79f28bfaf73b66b7b1562d2468f94aa03bd12", "lessThan": "37a5dcd6837fc2afc44a7bc3ed8af4e983783d46", "status": "affected", "versionType": "git" }, { "version": "0fe79f28bfaf73b66b7b1562d2468f94aa03bd12", "lessThan": "e907bf694ed55bdfe421be99dba35751a655df25", "status": "affected", "versionType": "git" }, { "version": "0fe79f28bfaf73b66b7b1562d2468f94aa03bd12", "lessThan": "03cb8cc2961f5f781d12e903782cb3815ed84b1c", "status": "affected", "versionType": "git" }, { "version": "0fe79f28bfaf73b66b7b1562d2468f94aa03bd12", "lessThan": "3ce832e2bd431d0c12ba525ed73ad8fbc4191da5", "status": "affected", "versionType": "git" }, { "version": "0fe79f28bfaf73b66b7b1562d2468f94aa03bd12", "lessThan": "81be30c1f5f2bffda1f04c0efd0746af10b9643a", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/gro.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.154", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.106", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.47", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.106" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.18.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/37a5dcd6837fc2afc44a7bc3ed8af4e983783d46" }, { "url": "https://git.kernel.org/stable/c/e907bf694ed55bdfe421be99dba35751a655df25" }, { "url": "https://git.kernel.org/stable/c/03cb8cc2961f5f781d12e903782cb3815ed84b1c" }, { "url": "https://git.kernel.org/stable/c/3ce832e2bd431d0c12ba525ed73ad8fbc4191da5" }, { "url": "https://git.kernel.org/stable/c/81be30c1f5f2bffda1f04c0efd0746af10b9643a" } ], "title": "net: gro: properly validate BIG TCP aggregation criteria", "x_generator": { "engine": "bippy-1.2.0" } } } }