{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64046", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.029Z", "datePublished": "2026-07-19T15:39:31.129Z", "dateUpdated": "2026-08-05T12:38:38.201Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:38:38.201Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tls: prevent chain-after-chain in plain text SG\n\nSashiko points out that if end = 0 (start != 0) the current\ncode will create a chain link to content type right after\nthe wrap link:\n\n This would create a chain where the wrap link points directly\n to another chain link. The scatterlist API sg_next iterator\n does not recursively resolve consecutive chain links.\n\nmeaning this is illegal input to crypto.\n\nThe wrapping link is unnecessary if end = 0. end is the entry after\nthe last one used so end = 0 means there's nothing pushed after\nthe wrap:\n\n end start i\n v v v\n [ ]...[ ][ d ][ d ][ d ][ d ][rsv for wrap]\n\nSkip the wrapping in this case.\n\nTLS 1.3 can use the \"wrapping slot\" for it's chaining if end = 0.\nThis avoids the chain-after-chain.\n\nMove the wrap chaining before marking END and chaining off content\ntype, that feels like more logical ordering to me, but should not\nmatter from functional perspective." } ], "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 kTLS software TX (`tls_push_record` in `net/tls/tls_sw.c`), reached when encrypting outbound TLS 1.3 records on a connected socket; a remote TLS peer triggers this path on internet-facing servers and L7 proxies (kTLS+sockmap) by causing the host to send TLS responses.\nAC:L - The wrapped `sk_msg` ring state (`end=0`, `start!=0`) needed to hit the chain-after-chain bug is deterministically created via BPF `sk_msg` helpers (`bpf_msg_push_data`/`bpf_msg_pop_data`), which the attacker controls on the local path or can steer on servers whose sockmap programs manipulate messages based on connection traffic.\nPR:N - Exploitation does not require Linux capabilities on the attacking side when targeting a TLS service already running kTLS with sockmap; any unauthenticated remote client that completes a TLS 1.3 handshake and causes record transmission can reach the vulnerable encrypt path.\nUI:N - No victim user action beyond normal automated TLS server/client operation is required; triggering the bug is achieved through crafted network traffic and/or syscall-driven sends on an already-established kTLS socket.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same host/kernel security boundary, not a cross-boundary escape such as VM guest-to-host or IOMMU bypass.\nC:H - Passing a scatterlist with consecutive chain links to `crypto_aead_encrypt` is illegal; the crypto scatterwalk treats chain entries as data pages, causing out-of-bounds kernel memory reads and information disclosure primitives.\nI:H - The malformed scatterlist fed to AEAD encryption can cause the crypto layer to write ciphertext to incorrect kernel addresses, providing a memory corruption primitive that can be developed into arbitrary kernel write or code execution.\nA:H - Invalid scatterlist traversal in the crypto path can dereference bogus page pointers and kernel-oops the system; encryption failure also invokes `tls_err_abort`, reliably disrupting the affected TLS connection and potentially the hosting service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tls/tls_sw.c" ], "versions": [ { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "49a5faaa471ddcd37b6893970c9916eb836e7c31", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "91359966e247c0244c66d50bbb8e74aefa4321c3", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "410351158dfef2d67fea6603680b3a6013c6ed9d", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "acdc12b71c9aa4be5dcd2c8062753c6d2033e235", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "929b1548e63ac72e104c07d8ee8cbbeeba2fa89a", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "af855f4c966afafef74faf8390c7b86568c0d46d", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36", "status": "affected", "versionType": "git" }, { "version": "9aaaa56845a06aeabdd597cbe19492dc01f281ec", "lessThan": "ff26a0e8377dec07e4a7230db7675bed1b9a6d03", "status": "affected", "versionType": "git" }, { "version": "d529d6c9f7e3aaeac13c4948f79799ccb825f29d", "status": "affected", "versionType": "git" }, { "version": "5.4.14", "lessThan": "5.5", "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/tls/tls_sw.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "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": "5.5", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/49a5faaa471ddcd37b6893970c9916eb836e7c31" }, { "url": "https://git.kernel.org/stable/c/91359966e247c0244c66d50bbb8e74aefa4321c3" }, { "url": "https://git.kernel.org/stable/c/410351158dfef2d67fea6603680b3a6013c6ed9d" }, { "url": "https://git.kernel.org/stable/c/acdc12b71c9aa4be5dcd2c8062753c6d2033e235" }, { "url": "https://git.kernel.org/stable/c/929b1548e63ac72e104c07d8ee8cbbeeba2fa89a" }, { "url": "https://git.kernel.org/stable/c/af855f4c966afafef74faf8390c7b86568c0d46d" }, { "url": "https://git.kernel.org/stable/c/b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36" }, { "url": "https://git.kernel.org/stable/c/ff26a0e8377dec07e4a7230db7675bed1b9a6d03" } ], "title": "net: tls: prevent chain-after-chain in plain text SG", "x_generator": { "engine": "bippy-1.2.0" } } } }