{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-39682", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.113Z", "datePublished": "2025-09-05T17:20:48.657Z", "dateUpdated": "2026-08-05T12:04:31.384Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:04:31.384Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: fix handling of zero-length records on the rx_list\n\nEach recvmsg() call must process either\n - only contiguous DATA records (any number of them)\n - one non-DATA record\n\nIf the next record has different type than what has already been\nprocessed we break out of the main processing loop. If the record\nhas already been decrypted (which may be the case for TLS 1.3 where\nwe don't know type until decryption) we queue the pending record\nto the rx_list. Next recvmsg() will pick it up from there.\n\nQueuing the skb to rx_list after zero-copy decrypt is not possible,\nsince in that case we decrypted directly to the user space buffer,\nand we don't have an skb to queue (darg.skb points to the ciphertext\nskb for access to metadata like length).\n\nOnly data records are allowed zero-copy, and we break the processing\nloop after each non-data record. So we should never zero-copy and\nthen find out that the record type has changed. The corner case\nwe missed is when the initial record comes from rx_list, and it's\nzero length." } ], "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 triggered entirely by the sequence and content of TLS records arriving from the remote peer on a kTLS-enabled TCP socket (net/tls RX path); no local access is needed. Any kTLS RX consumer — OpenSSL-with-kTLS servers/clients, NFS-over-TLS, SMB/RPC-over-TLS via net/handshake — is remotely reachable over the network.\nAC:L - The attacker sends three back-to-back records ([DATA][zero-length non-DATA][DATA]) and the corruption occurs deterministically on the victim's ordinary recvmsg() loop, with no race to win and no memory-layout dependency; the kernel selftest added with the fix reproduces it in one shot. TLS 1.2 is zero-copy-capable by default (zc_capable = rx_no_pad || version != TLS_1_3_VERSION), so no unusual kernel config or sockopt is required.\nPR:N - The attacker is the remote TLS peer, which holds no privileges on the target system — an anonymous client completing a server-authenticated TLS handshake with a kTLS server, or a malicious server that a kTLS client connects to, suffices. This matches the repo's PR:N scoring of the comparable remote-peer net/tls bug CVE-2025-39946.\nUI:N - The victim application only has to run its normal recvmsg() loop on an already-established kTLS socket; no click, mount, file open, or any other victim action is required. The attacker drives the entire trigger from the wire.\nS:U - The corruption is confined to kernel skb/slab state within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed. Standard in-kernel memory corruption is Scope:Unchanged.\nC:H - The strparser anchor is queued on rx_list after tcp_read_done() already released its backing TCP skbs, so the next recvmsg() copies freed kernel heap memory straight into the userspace buffer via skb_copy_datagram_msg(). This is a directly usable, repeatable kernel-memory disclosure primitive, not a bounded pointer leak.\nI:H - The live strp->anchor is consume_skb()'d by process_rx_list() while the strparser still uses it, after which incoming attacker-controlled TCP data is written into the freed sk_buff/skb_shared_info (skb_fill_page_desc, tls_strp_load_anchor_with_queue), and socket teardown double-frees the anchor and its frag_list skbs. This yields attacker-controlled write-after-free and freelist corruption suitable for control-flow hijack.\nA:H - The use-after-free and double-free of the anchor and of already-released TCP receive-queue skbs reliably corrupt slab state, producing oopses/panics and list corruption. Any remote peer can repeat this on every connection, giving a trivial remote kernel-crash DoS." } ] } ], "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": "84c61fe1a75b4255df1e1e7c054c9e6d048da417", "lessThan": "2902c3ebcca52ca845c03182000e8d71d3a5196f", "status": "affected", "versionType": "git" }, { "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417", "lessThan": "c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677", "status": "affected", "versionType": "git" }, { "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417", "lessThan": "3439c15ae91a517cf3c650ea15a8987699416ad9", "status": "affected", "versionType": "git" }, { "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417", "lessThan": "29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e", "status": "affected", "versionType": "git" }, { "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417", "lessThan": "62708b9452f8eb77513115b17c4f8d1a22ebf843", "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/tls/tls_sw.c" ], "versions": [ { "version": "6.0", "status": "affected" }, { "version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.149", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.103", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.44", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.4", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "6.0", "versionEndExcluding": "6.1.149" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.6.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.16.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f" }, { "url": "https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677" }, { "url": "https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9" }, { "url": "https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e" }, { "url": "https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843" } ], "title": "tls: fix handling of zero-length records on the rx_list", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:42:13.673Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:06:08.852Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC CN 4100", "versions": [ { "status": "affected", "version": "0", "lessThan": "V5.0", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html" } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2025-39682", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-06-10T20:42:07.158655Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-11T18:44:19.531Z" } } ] } }