{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-64046", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-64046" ], "published": "2026-07-19T15:41:06Z", "summary": "net: tls: prevent chain-after-chain in plain text SG", "details": "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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.175", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-64046" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/49a5faaa471ddcd37b6893970c9916eb836e7c31" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/91359966e247c0244c66d50bbb8e74aefa4321c3" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/410351158dfef2d67fea6603680b3a6013c6ed9d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/acdc12b71c9aa4be5dcd2c8062753c6d2033e235" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/929b1548e63ac72e104c07d8ee8cbbeeba2fa89a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/af855f4c966afafef74faf8390c7b86568c0d46d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ff26a0e8377dec07e4a7230db7675bed1b9a6d03" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T13:16:28Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 9.8, "cvss_v3_severity": "Critical", "scenario": "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." } } }