{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68119", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.369Z", "datePublished": "2026-08-10T11:58:39.026Z", "dateUpdated": "2026-08-17T04:59:09.650Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:59:09.650Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: initialize standalone TCP-AO response padding\n\ntcp_v4_send_ack() and tcp_v6_send_response() construct standalone TCP\nresponses with TCP-AO options. The option length carries the actual MAC\nlength, but the TCP header length includes the option rounded up to a\nfour-byte boundary.\n\ntcp_ao_hash_hdr() writes the MAC only. Thus, when the MAC length is not\nfour-byte aligned, the one to three bytes after the MAC are left\nuninitialized and may be transmitted. For the normal TCP-AO hashing\nmode, those bytes also have to be initialized before computing the MAC.\n\nInitialize only the alignment padding in the TCP-AO branches, before\nhashing the header. Use TCPOPT_NOP, as in the normal TCP-AO output path.\nThis avoids adding work to non-AO TCP responses while preserving a valid\nauthenticated header." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - Remote attackers reach tcp_v4_send_ack() and tcp_v6_send_response() by sending IPv4/IPv6 TCP segments into tcp_v4_rcv()/tcp_v6_rcv() SYN-RECV, TIME-WAIT, and reset paths that build standalone TCP-AO-signed ACK/RST replies transmitted back over the network.\nAC:L - On Internet-facing TCP-AO deployments (BGP/route-server successors to TCP-MD5), an attacker reliably elicits qualifying standalone responses by sending crafted TCP segments; no race, timing lottery, or uncontrollable memory layout is required beyond the peer using a non-4-byte-aligned MAC length.\nPR:N - The uninitialized bytes are returned to the remote packet sender in standalone TCP-AO ACK/RST replies; triggering requires only network reachability to a TCP-AO-enabled listener or an existing TCP-AO TIME-WAIT socket, with no local credentials on the victim host.\nUI:N - No end-user action is needed beyond normal exposure of a TCP-AO-protected network service; the attacker alone sends the triggering TCP segments and captures the padded replies.\nS:U - Kernel stack or skb memory is disclosed to a remote TCP peer within the same host kernel security authority; this is not a VM escape, IOMMU bypass, or other cross-boundary scope change.\nC:H - One to three uninitialized bytes in TCP-AO option alignment padding from the on-stack IPv4 response buffer or IPv6 skb head are transmitted on every qualifying standalone ACK/RST and can be harvested repeatedly to recover kernel stack or skb contents.\nI:N - The bug only fails to initialize alignment padding before transmission; it does not write to or corrupt kernel, socket, or application memory.\nA:N - Standalone TCP-AO responses are still transmitted successfully with no kernel oops, panic, hang, or denial of service; only confidentiality of the leaked padding bytes is affected." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/tcp_ipv4.c", "net/ipv6/tcp_ipv6.c" ], "versions": [ { "version": "decde2586b34b99684faff1eab41e5c496c27fb6", "lessThan": "bbb7db8c74b0b5d17a695136f0f0806ecd0118f6", "status": "affected", "versionType": "git" }, { "version": "decde2586b34b99684faff1eab41e5c496c27fb6", "lessThan": "fadaff3f66e124c3a62237f9c881819a8ac90309", "status": "affected", "versionType": "git" }, { "version": "decde2586b34b99684faff1eab41e5c496c27fb6", "lessThan": "a859b280441fb02f64ed4037f03d5c0c34a7a595", "status": "affected", "versionType": "git" }, { "version": "decde2586b34b99684faff1eab41e5c496c27fb6", "lessThan": "e1a9d3cc11829c5414a75eb39c704f461936eb24", "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/ipv4/tcp_ipv4.c", "net/ipv6/tcp_ipv6.c" ], "versions": [ { "version": "6.7", "status": "affected" }, { "version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.7", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bbb7db8c74b0b5d17a695136f0f0806ecd0118f6" }, { "url": "https://git.kernel.org/stable/c/fadaff3f66e124c3a62237f9c881819a8ac90309" }, { "url": "https://git.kernel.org/stable/c/a859b280441fb02f64ed4037f03d5c0c34a7a595" }, { "url": "https://git.kernel.org/stable/c/e1a9d3cc11829c5414a75eb39c704f461936eb24" } ], "title": "tcp: initialize standalone TCP-AO response padding", "x_generator": { "engine": "bippy-1.2.0" } } } }