{"id":"CVE-2026-99139","state":"PUBLISHED","title":"tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)\n\ndo_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding\nrcu_read_lock(). Since commit 0baf26b0fcd7 (\"bpf: tcp: Support\ntcp_congestion_ops in bpf\"), icsk_ca_ops can point to dynamically\nallocated BPF struct_ops memory that may be freed concurrently via\nsetsockopt(TCP_CONGESTION), leading to a use-after-free.\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60\n  Read of size 16 at addr ffff888013505260 by task exploit/149\n   _copy_to_user+0x37/0x60\n   do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by holding rcu_read_lock() around the ca_ops->name access,\nusing READ_ONCE() to load icsk_ca_ops, and copying the name to a\nstack buffer before releasing the lock. Also annotate the relevant\nicsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN\ndata-race issue.","publishedAt":"2026-10-28T10:34:50.674Z","updatedAt":"2026-10-30T12:42:11.824Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"a60e62705c17534d6b6539de7b3a40c259e6827f","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"08dc5c62c09653d1c4ba67a009beb138486c2604","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"c1804ef016392dd91267d2207ee43b1de34302ca","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"a8e45471afa230c1431c26c8e99ec24377e3b514","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"5271b79b7ad68dcb222e893773f92bdabf7750f3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/tcp.c","net/ipv4/tcp_cong.c","net/ipv4/tcp_dctcp.c","net/ipv4/tcp_minisocks.c","net/ipv4/tcp_output.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/tcp.c","net/ipv4/tcp_cong.c","net/ipv4/tcp_dctcp.c","net/ipv4/tcp_minisocks.c","net/ipv4/tcp_output.c"]}],"references":["https://git.kernel.org/stable/c/a60e62705c17534d6b6539de7b3a40c259e6827f","https://git.kernel.org/stable/c/4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03","https://git.kernel.org/stable/c/08dc5c62c09653d1c4ba67a009beb138486c2604","https://git.kernel.org/stable/c/c1804ef016392dd91267d2207ee43b1de34302ca","https://git.kernel.org/stable/c/a8e45471afa230c1431c26c8e99ec24377e3b514","https://git.kernel.org/stable/c/5271b79b7ad68dcb222e893773f92bdabf7750f3"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99139.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99139","state":"PUBLISHED","datePublished":"2026-10-28T10:34:50.674Z","dateUpdated":"2026-10-30T12:42:11.824Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.395Z"},"containers":{"cna":{"title":"tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)\n\ndo_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding\nrcu_read_lock(). Since commit 0baf26b0fcd7 (\"bpf: tcp: Support\ntcp_congestion_ops in bpf\"), icsk_ca_ops can point to dynamically\nallocated BPF struct_ops memory that may be freed concurrently via\nsetsockopt(TCP_CONGESTION), leading to a use-after-free.\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60\n  Read of size 16 at addr ffff888013505260 by task exploit/149\n   _copy_to_user+0x37/0x60\n   do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by holding rcu_read_lock() around the ca_ops->name access,\nusing READ_ONCE() to load icsk_ca_ops, and copying the name to a\nstack buffer before releasing the lock. Also annotate the relevant\nicsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN\ndata-race issue."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"a60e62705c17534d6b6539de7b3a40c259e6827f","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"08dc5c62c09653d1c4ba67a009beb138486c2604","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"c1804ef016392dd91267d2207ee43b1de34302ca","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"a8e45471afa230c1431c26c8e99ec24377e3b514","versionType":"git"},{"version":"0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2","status":"affected","lessThan":"5271b79b7ad68dcb222e893773f92bdabf7750f3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/tcp.c","net/ipv4/tcp_cong.c","net/ipv4/tcp_dctcp.c","net/ipv4/tcp_minisocks.c","net/ipv4/tcp_output.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/tcp.c","net/ipv4/tcp_cong.c","net/ipv4/tcp_dctcp.c","net/ipv4/tcp_minisocks.c","net/ipv4/tcp_output.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a60e62705c17534d6b6539de7b3a40c259e6827f"},{"url":"https://git.kernel.org/stable/c/4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03"},{"url":"https://git.kernel.org/stable/c/08dc5c62c09653d1c4ba67a009beb138486c2604"},{"url":"https://git.kernel.org/stable/c/c1804ef016392dd91267d2207ee43b1de34302ca"},{"url":"https://git.kernel.org/stable/c/a8e45471afa230c1431c26c8e99ec24377e3b514"},{"url":"https://git.kernel.org/stable/c/5271b79b7ad68dcb222e893773f92bdabf7750f3"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:42:11.824Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}