{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68284", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.379Z", "datePublished": "2026-08-10T12:02:16.572Z", "dateUpdated": "2026-08-19T16:32:41.174Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:32:41.174Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()\n\ntcp_bpf_sendmsg() keeps msg_tx across sk_stream_wait_memory(), which\ndrops and reacquires the socket lock. Its error path tries to decide\nwhether msg_tx names the local temporary message by comparing it with\nthe current value of psock->cork.\n\nThis comparison is unsafe when two threads send on the same socket:\n\n Thread A Thread B\n msg_tx = psock->cork\n sk_msg_alloc() fails\n sk_stream_wait_memory()\n releases the socket lock acquires the socket lock\n completes the cork\n psock->cork = NULL\n frees the cork\n reacquires the socket lock\n msg_tx != psock->cork\n sk_msg_free(msg_tx)\n\nThe stale cork is therefore mistaken for the local temporary message\nand freed again. KASAN reported:\n\n BUG: KASAN: slab-use-after-free in sk_msg_free+0x49/0x50\n Read of size 4 at addr ffff88810c908800 by task poc/90\n Call Trace:\n sk_msg_free+0x49/0x50\n tcp_bpf_sendmsg+0x14f5/0x1cc0\n __sys_sendto+0x32c/0x3a0\n __x64_sys_sendto+0xdb/0x1b0\n Allocated by task 89:\n __kasan_kmalloc+0x8f/0xa0\n tcp_bpf_sendmsg+0x16b3/0x1cc0\n Freed by task 91:\n __kasan_slab_free+0x43/0x70\n kfree+0x131/0x3c0\n tcp_bpf_sendmsg+0xec3/0x1cc0\n\nmsg_tx can only name the stack-local tmp or the shared cork. Check for\ntmp directly so a changed psock->cork cannot turn a shared message into\nan apparent local one." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is triggered by local `sendmsg()`/`sendto()` syscalls issued concurrently by two threads on the same TCP socket attached to a BPF sockmap; the remote peer cannot drive the race, so this is a local attack surface.\nAC:L - The attacker controls both sides of the race: it owns both sending threads, can force the `wait_for_memory` path deterministically with a small SO_SNDBUF plus a large blocking send, and can force `sk_stream_wait_memory()` to fail via SO_SNDTIMEO or a socket error, making the stale-cork free reliably reachable.\nPR:L - Once the sockmap and sk_msg verdict/cork program are installed by the platform (a standard deployment such as Cilium/Istio sockops acceleration), an ordinary unprivileged local process owning a socket in the map triggers the bug with plain send syscalls; no capability check guards `tcp_bpf_sendmsg()` itself.\nUI:N - The attacker's own two threads perform all the required sends; no action by any other user or victim process is needed.\nS:U - The use-after-free corrupts kernel slab and page state within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `sk_msg_free()` reads the freed `sk_msg` cork object (KASAN slab-use-after-free read), and by reclaiming that slab object with attacker-groomed data the freed scatterlist can be steered to leak or expose arbitrary kernel memory contents.\nI:H - Beyond the stale read, the path re-frees the cork's scatterlist pages and uncharges socket memory, giving a double-free/page-refcount-underflow primitive on an attacker-groomable slab object, which is classically leveraged into arbitrary kernel write and control-flow hijack.\nA:H - The use-after-free and duplicate page release corrupt slab and page allocator state, reliably producing a kernel oops or panic and taking the whole system down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/tcp_bpf.c" ], "versions": [ { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "0688e6fe599d2d39147ae9ece97944c6e1815ebf", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "b2bcbeabfd843d47468fa095b1bd08ddb90cf616", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "54be47e7cbb936429c3bbdfc526ea943954aaf80", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "ee762f684eefa59de34d9ed93cab08336e834f47", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "cde4d6bcd9b73073c66498f6723c7b364c4dbc18", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "786d690257ec7a0c839f8710456e444ce3f1348b", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "752b1159ed5d0c48fe169a3721b96660a9822aa1", "status": "affected", "versionType": "git" }, { "version": "604326b41a6fb9b4a78b6179335decee0365cd8c", "lessThan": "2d66a033864e27ab8d5e44cb36f31d9d2413bee4", "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_bpf.c" ], "versions": [ { "version": "4.20", "status": "affected" }, { "version": "0", "lessThan": "4.20", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "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": "4.20", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0688e6fe599d2d39147ae9ece97944c6e1815ebf" }, { "url": "https://git.kernel.org/stable/c/b2bcbeabfd843d47468fa095b1bd08ddb90cf616" }, { "url": "https://git.kernel.org/stable/c/54be47e7cbb936429c3bbdfc526ea943954aaf80" }, { "url": "https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47" }, { "url": "https://git.kernel.org/stable/c/cde4d6bcd9b73073c66498f6723c7b364c4dbc18" }, { "url": "https://git.kernel.org/stable/c/786d690257ec7a0c839f8710456e444ce3f1348b" }, { "url": "https://git.kernel.org/stable/c/752b1159ed5d0c48fe169a3721b96660a9822aa1" }, { "url": "https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4" } ], "title": "bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()", "x_generator": { 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