--- id: CVE-2024-36904 title: |- In the Linux kernel, the following vulnerability has been resolved: tcp: Use refcount_inc_not_zero() in tcp_twsk_unique(). Anderson Nascimento reported a use-after-free splat in tcp_twsk_unique() with nice analysis. Since commit ec94c… summary: |- In the Linux kernel, the following vulnerability has been resolved: tcp: Use refcount_inc_not_zero() in tcp_twsk_unique(). Anderson Nascimento reported a use-after-free splat in tcp_twsk_unique() with nice analysis. Since commit ec94c… severity: high cvss: 7.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H' cwe: - CWE-416 vendor: linux product: linux_kernel affected: - 'linux_kernel >= 4.16, < 4.19.314' - 'linux_kernel >= 4.20, < 5.4.276' - 'linux_kernel >= 5.5, < 5.10.217' - 'linux_kernel >= 5.11, < 5.15.159' - 'linux_kernel >= 5.16, < 6.1.91' - 'linux_kernel >= 6.2, < 6.6.31' - 'linux_kernel >= 6.7, < 6.8.10' - linux_kernel = 6.9 - debian_linux = 10.0 patched: - linux_kernel 6.8.10 published: '2024-05-30' updated: '2026-10-15' sourceUpdated: '2026-10-15T01:18:24.407' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2024-36904' references: - url: 'https://git.kernel.org/stable/c/13ed7cdf079686ccd3618335205700c03f6fb446' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/1796ca9c6f5bd50554214053af5f47d112818ee3' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/1d9cf07810c30ef7948879567d10fd1f01121d34' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/27b0284d8be182a81feb65581ab6a724dfd596e8' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/517e32ea0a8c72202d0d8aa8df50a7cd3d6fdefc' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/6e48faad92be13166184d21506e4e54c79c13adc' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/84546cc1aeeb4df3e444b18a4293c9823f974be9' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/f2db7230f73a80dbb179deab78f88a7947f0ab7e' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/13ed7cdf079686ccd3618335205700c03f6fb446' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/1796ca9c6f5bd50554214053af5f47d112818ee3' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/1d9cf07810c30ef7948879567d10fd1f01121d34' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/27b0284d8be182a81feb65581ab6a724dfd596e8' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/517e32ea0a8c72202d0d8aa8df50a7cd3d6fdefc' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/6e48faad92be13166184d21506e4e54c79c13adc' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/84546cc1aeeb4df3e444b18a4293c9823f974be9' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://git.kernel.org/stable/c/f2db7230f73a80dbb179deab78f88a7947f0ab7e' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2024/06/msg00019.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://security.netapp.com/advisory/ntap-20240905-0004/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e - url: 'https://cert-portal.siemens.com/productcert/html/ssa-613116.html' label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e tags: - nvd - cve.org epss: 0.00614 epssPercentile: 0.49185 ingestedAt: '2026-10-15T03:30:12.700Z' ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2024-06-12T19:20:22.181493Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: tcp: Use refcount_inc_not_zero() in tcp_twsk_unique(). Anderson Nascimento reported a use-after-free splat in tcp_twsk_unique() with nice analysis. Since commit ec94c2696f0b ("tcp/dccp: avoid one atomic operation for timewait hashdance"), inet_twsk_hashdance() sets TIME-WAIT socket's sk_refcnt after putting it into ehash and releasing the bucket lock. Thus, there is a small race window where other threads could try to reuse the port during connect() and call sock_hold() in tcp_twsk_unique() for the TIME-WAIT socket with zero refcnt. If that happens, the refcnt taken by tcp_twsk_unique() is overwritten and sock_put() will cause underflow, triggering a real use-after-free somewhere else. To avoid the use-after-free, we need to use refcount_inc_not_zero() in tcp_twsk_unique() and give up on reusing the port if it returns false. [0]: refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 1039313 at lib/refcount.c:25 refcount_warn_saturate+0xe5/0x110 CPU: 0 PID: 1039313 Comm: trigger Not tainted 6.8.6-200.fc39.x86_64 #1 Hardware name: VMware, Inc. VMware20,1/440BX Desktop Reference Platform, BIOS VMW201.00V.21805430.B64.2305221830 05/22/2023 RIP: 0010:refcount_warn_saturate+0xe5/0x110 Code: 42 8e ff 0f 0b c3 cc cc cc cc 80 3d aa 13 ea 01 00 0f 85 5e ff ff ff 48 c7 c7 f8 8e b7 82 c6 05 96 13 ea 01 01 e8 7b 42 8e ff <0f> 0b c3 cc cc cc cc 48 c7 c7 50 8f b7 82 c6 05 7a 13 ea 01 01 e8 RSP: 0018:ffffc90006b43b60 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff888009bb3ef0 RCX: 0000000000000027 RDX: ffff88807be218c8 RSI: 0000000000000001 RDI: ffff88807be218c0 RBP: 0000000000069d70 R08: 0000000000000000 R09: ffffc90006b439f0 R10: ffffc90006b439e8 R11: 0000000000000003 R12: ffff8880029ede84 R13: 0000000000004e20 R14: ffffffff84356dc0 R15: ffff888009bb3ef0 FS: 00007f62c10926c0(0000) GS:ffff88807be00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020ccb000 CR3: 000000004628c005 CR4: 0000000000f70ef0 PKRU: 55555554 Call Trace: ? refcount_warn_saturate+0xe5/0x110 ? __warn+0x81/0x130 ? refcount_warn_saturate+0xe5/0x110 ? report_bug+0x171/0x1a0 ? refcount_warn_saturate+0xe5/0x110 ? handle_bug+0x3c/0x80 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? refcount_warn_saturate+0xe5/0x110 tcp_twsk_unique+0x186/0x190 __inet_check_established+0x176/0x2d0 __inet_hash_connect+0x74/0x7d0 ? __pfx___inet_check_established+0x10/0x10 tcp_v4_connect+0x278/0x530 __inet_stream_connect+0x10f/0x3d0 inet_stream_connect+0x3a/0x60 __sys_connect+0xa8/0xd0 __x64_sys_connect+0x18/0x20 do_syscall_64+0x83/0x170 entry_SYSCALL_64_after_hwframe+0x78/0x80 RIP: 0033:0x7f62c11a885d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a3 45 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007f62c1091e58 EFLAGS: 00000296 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000020ccb004 RCX: 00007f62c11a885d RDX: 0000000000000010 RSI: 0000000020ccb000 RDI: 0000000000000003 RBP: 00007f62c1091e90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 00007f62c10926c0 R13: ffffffffffffff88 R14: 0000000000000000 R15: 00007ffe237885b0 ## Affected - `linux_kernel >= 4.16, < 4.19.314` - `linux_kernel >= 4.20, < 5.4.276` - `linux_kernel >= 5.5, < 5.10.217` - `linux_kernel >= 5.11, < 5.15.159` - `linux_kernel >= 5.16, < 6.1.91` - `linux_kernel >= 6.2, < 6.6.31` - `linux_kernel >= 6.7, < 6.8.10` - `linux_kernel = 6.9` - `debian_linux = 10.0` ## Remediation Upgrade past the affected range: - `linux_kernel 6.8.10`