{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63912", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.020Z", "datePublished": "2026-07-19T14:55:17.188Z", "dateUpdated": "2026-08-05T12:37:06.161Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:37:06.161Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: esp: restore combined single-frag length gate\n\nThe ESP out-of-place fast path appends the trailer in esp_output_head()\nbefore esp_output_tail() allocates the destination page frag. The\nhead-side gate currently checks skb->data_len and tailen separately, but\nthe tail code allocates a single destination frag from the combined\npost-trailer skb->data_len.\n\nReject the page-frag fast path when the combined aligned length exceeds a\npage. Otherwise skb_page_frag_refill() may fall back to a single page while\nthe destination sg still spans the combined skb->data_len.\n\nRestore this combined-length page gate for both IPv4 and IPv6." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is in the ESP outbound encryption path reached when IPsec-protected traffic is sent through xfrm (e.g., from an internet-facing VPN/tunnel gateway encrypting responses or forwarded flows to a remote peer). A network peer can influence outbound skb fragment sizes to hit the vulnerable fast path without local shell access.\nAC:L - An attacker can reliably craft payload sizes so ALIGN(skb->data_len) and ALIGN(tailen) each pass the broken per-field PAGE_SIZE gate while their combined aligned length exceeds PAGE_SIZE, repeatedly probing until the out-of-place page-frag path is taken.\nPR:N - Exploitation does not require configuring xfrm or host admin rights; it only needs the target to already run ESP and the attacker to send traffic that is encrypted on output (e.g., as a remote VPN/site-to-site peer), which is network-layer access rather than local OS privilege.\nUI:N - Triggering the vulnerable ESP output path requires only attacker-controlled network traffic and does not depend on any victim user action such as mounting a filesystem or opening a file.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security authority, not a cross-boundary escape such as guest-to-host VM breakout or IOMMU bypass.\nC:H - The flaw is a heap out-of-bounds write during AEAD encryption over an undersized page frag; such memory corruption can expose adjacent kernel objects and be leveraged for arbitrary memory disclosure, not merely a bounded leak.\nI:H - Writing past the allocated page-frag buffer corrupts adjacent heap memory and can be developed into arbitrary write or control-flow hijack primitives, matching kernel guidance for out-of-bounds writes.\nA:H - Corrupting kernel heap memory during crypto output can cause immediate kernel oops/panic or persistent instability, and repeated triggering can deny service on VPN gateways and other IPsec endpoints." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/esp4.c", "net/ipv6/esp6.c" ], "versions": [ { "version": "c075c3ea031757f8ea2d34567565b61a868c08d5", "lessThan": "566295735530ee513326049b0540f32ec050bf2e", "status": "affected", "versionType": "git" }, { "version": "a583f2f3c8788bffd7fd7baeb76bd6d80543d7ea", "lessThan": "5d7ab86e2b6bc23054616bf6ac562013bf60af8c", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "36519e3d941fc99d3b52c134dbaf311f987a4708", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "322e48187e0245ab2fff6fec2220b0cae677dbec", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "b84091ceddc9f133229dceab3ccc930bf27f9cba", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "c093468aea8277f77272a4f199b2e15e19cabb59", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "65f3b3fc2347b89fe21db1e92c7681368415f095", "status": "affected", "versionType": "git" }, { "version": "5bd8baab087dff657e05387aee802e70304cc813", "lessThan": "dfa0d7b0ff1eb6b2c416b8fdb9b4f2cefba57a40", "status": "affected", "versionType": "git" }, { "version": "2c66b0c95bb0aa7652ba1eba293d0d5993b35a38", "status": "affected", "versionType": "git" }, { "version": "ef6f83df1209a7d9bd1c605a62457d4c00f9179e", "status": "affected", "versionType": "git" }, { "version": "3defefd22ad5fbbe639b6157fb7e6311b2bf333d", "status": "affected", "versionType": "git" }, { "version": "b657030870bb5351c5b1e84d4e9f186da6ca0496", "status": "affected", "versionType": "git" }, { "version": "5.10.113", "lessThan": "5.10.259", "status": "affected", "versionType": "semver" }, { "version": "5.15.36", "lessThan": "5.15.210", "status": "affected", "versionType": "semver" }, { "version": "4.14.288", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.252", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.205", "lessThan": "5.5", "status": "affected", "versionType": "semver" }, { "version": "5.17.5", "lessThan": "5.18", "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/ipv4/esp4.c", "net/ipv6/esp6.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "5.10.113", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.36", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.288" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.252" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.205" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/566295735530ee513326049b0540f32ec050bf2e" }, { "url": "https://git.kernel.org/stable/c/5d7ab86e2b6bc23054616bf6ac562013bf60af8c" }, { "url": "https://git.kernel.org/stable/c/36519e3d941fc99d3b52c134dbaf311f987a4708" }, { "url": "https://git.kernel.org/stable/c/322e48187e0245ab2fff6fec2220b0cae677dbec" }, { "url": "https://git.kernel.org/stable/c/b84091ceddc9f133229dceab3ccc930bf27f9cba" }, { "url": "https://git.kernel.org/stable/c/c093468aea8277f77272a4f199b2e15e19cabb59" }, { "url": "https://git.kernel.org/stable/c/65f3b3fc2347b89fe21db1e92c7681368415f095" }, { "url": "https://git.kernel.org/stable/c/dfa0d7b0ff1eb6b2c416b8fdb9b4f2cefba57a40" } ], "title": "xfrm: esp: restore combined single-frag length gate", "x_generator": { "engine": "bippy-1.2.0" } } } }