{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98852", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.376Z", "datePublished": "2026-10-18T15:50:55.946Z", "dateUpdated": "2026-10-21T12:57:32.027Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:57:32.027Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: extend IPv6 exthdr detection of tunneled packets\n\nCommit c4336a07eb6b (\"net: correctly handle tunneled traffic on IPV6_CSUM\nGSO fallback\") split skb_gso_has_extension_hdr() into mutually exclusive\nbranches on skb->encapsulation. This did not yet address all paths:\n\n1. With skb->encapsulation set, the outer header is not checked. IPv6\n tunnels such as ip6_gre and ip6_tunnel add an outer Destination\n Options header by default (encap_limit). Their GSO packets skip\n software GSO, then skb_csum_hwoffload_help() sees the outer extension\n header and calls skb_checksum_help() on the GSO skb, which warns and\n drops it.\n\n2. Tunnels over IPv6 without an outer transport header, such as\n ip6_tunnel, leave skb->transport_header at the inner transport\n header. skb_network_header_len() then spans the outer IPv6, tunnel\n and inner IP headers, a false positive.\n\n3. UDP tunnels without an inner network header, such as SCTP-in-UDP or\n PSP, have no inner IPv6 header to check. Decide on the outer header\n alone.\n\n4. Directly dereferencing inner_ip_hdr(skb)->version without\n skb_header_pointer() is unsafe.\n\nInstead, check ipv6_ext_hdr(nexthdr) on the outer IPv6 header and, if\nset, on the inner IPv6 header. Read the headers with skb_header_pointer().\nKeep the skb_network_header_len() check when !skb->encapsulation to also\ncatch encapsulated packets without skb->encapsulation (e.g., virtio).\n\nUse the same helper in skb_csum_hwoffload_help(). Its open coded test\nhas the false positive of (2) and ignores the inner header.\n\nBackground: checksum offload of tunneled packets invariants:\n\nNon-GSO skb:\n- If the inner packet is CHECKSUM_PARTIAL, Local Checksum Offload computes\n the outer checksum in software and the device offloads only the inner L4\n checksum.\n- If the inner packet is CHECKSUM_NONE (e.g., SCTP-in-UDP, ESP-in-UDP,\n Remote Checksum Offload), the device offloads the outer UDP or GRE\n checksum instead.\n\nGSO skb:\n- A device with NETIF_F_GSO_UDP_TUNNEL_CSUM or NETIF_F_GSO_GRE_CSUM\n computes both inner and outer checksums per segment.\n The outer checksum is seeded with only the pseudo-header checksum.\n\nA NETIF_F_IPV6_CSUM device must parse through the outer headers to\nreach the inner ones." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/dev.c" ], "versions": [ { "version": "ed71cf465c75f5688b07a35d373cd1d6b589c8ea", "lessThan": "fdbd83c2d929ec968b37d2f75149a79440e328ff", "status": "affected", "versionType": "git" }, { "version": "33670f780e0120c3dacda188c512bbffe0b6044c", "lessThan": "44ba9dc568c878b699d05e7cf699572dc9df4b59", "status": "affected", "versionType": "git" }, { "version": "a98b78116a27e2a57b696b569b2cb431c95cf9b6", "lessThan": "aa480f05aed7a9eee87d4a6fc90647fe9679c670", "status": "affected", "versionType": "git" }, { "version": "c4336a07eb6b2526dc2b62928b5104b41a7f81f5", "lessThan": "cabacdf98e09eb74599c4d97d7bd7fd659598fb7", "status": "affected", "versionType": "git" }, { "version": "c4336a07eb6b2526dc2b62928b5104b41a7f81f5", "lessThan": "5f0764cb1c81a9712bce605d38efe6d844a70b29", "status": "affected", "versionType": "git" }, { "version": "2094a7cf91b71367b649f991aacc7b579f793d0b", "status": "affected", "versionType": "git" }, { "version": "732fdeb2987c94b439d51f5cb9addddc2fc48c42", "status": "affected", "versionType": "git" }, { "version": "6.6.134", "lessThan": "6.6.160", "status": "affected", "versionType": "semver" }, { "version": "6.12.81", "lessThan": "6.12.113", "status": "affected", "versionType": "semver" }, { "version": "6.18.22", "lessThan": "6.18.56", "status": "affected", "versionType": "semver" }, { "version": "6.1.168", "lessThan": "6.2", "status": "affected", "versionType": "semver" }, { "version": "6.19.12", "lessThan": "6.20", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/dev.c" ], "versions": [ { "version": "7.0", "status": "affected" }, { "version": "0", "lessThan": "7.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.56", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.10", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.6.134", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.81", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.22", "versionEndExcluding": "6.18.56" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.2.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19.12" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fdbd83c2d929ec968b37d2f75149a79440e328ff" }, { "url": "https://git.kernel.org/stable/c/44ba9dc568c878b699d05e7cf699572dc9df4b59" }, { "url": "https://git.kernel.org/stable/c/aa480f05aed7a9eee87d4a6fc90647fe9679c670" }, { "url": "https://git.kernel.org/stable/c/cabacdf98e09eb74599c4d97d7bd7fd659598fb7" }, { "url": "https://git.kernel.org/stable/c/5f0764cb1c81a9712bce605d38efe6d844a70b29" } ], "title": "net: extend IPv6 exthdr detection of tunneled packets", "x_generator": { 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