Linux Kernel up to 7.0.9 bpf_iter_unix_seq_show lock deadlock

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.1.174/6.6.140/6.12.90/6.18.32/7.0.9. This vulnerability affects the function bpf_iter_unix_seq_show. Such manipulation of the argument lock leads to deadlock. This vulnerability is documented as CVE-2026-53035. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.1.174/6.6.140/6.12.90/6.18.32/7.0.9. Affected by this issue is the function bpf_iter_unix_seq_show. The manipulation of the argument lock with an unknown input leads to a deadlock vulnerability. Using CWE to declare the problem leads to CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix af_unix iter deadlock bpf_iter_unix_seq_show() may deadlock when lock_sock_fast() takes the fast path and the iter prog attempts to update a sockmap. Which ends up spinning at sock_map_update_elem()'s bh_lock_sock(): WARNING: possible recursive locking detected test_progs/1393 is trying to acquire lock: ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: sock_map_update_elem+0xdb/0x1f0 but task is already holding lock: ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: __lock_sock_fast+0x37/0xe0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(slock-AF_UNIX); lock(slock-AF_UNIX); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by test_progs/1393: #0: ffff88814b59c790 (&p->lock){+.+.}-{4:4}, at: bpf_seq_read+0x59/0x10d0 #1: ffff88811ec25fd8 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: bpf_seq_read+0x42c/0x10d0 #2: ffff88811ec25f58 (slock-AF_UNIX){+...}-{3:3}, at: __lock_sock_fast+0x37/0xe0 #3: ffffffff85a6a7c0 (rcu_read_lock){....}-{1:3}, at: bpf_iter_run_prog+0x51d/0xb00 Call Trace: dump_stack_lvl+0x5d/0x80 print_deadlock_bug.cold+0xc0/0xce __lock_acquire+0x130f/0x2590 lock_acquire+0x14e/0x2b0 _raw_spin_lock+0x30/0x40 sock_map_update_elem+0xdb/0x1f0 bpf_prog_2d0075e5d9b721cd_dump_unix+0x55/0x4f4 bpf_iter_run_prog+0x5b9/0xb00 bpf_iter_unix_seq_show+0x1f7/0x2e0 bpf_seq_read+0x42c/0x10d0 vfs_read+0x171/0xb20 ksys_read+0xff/0x200 do_syscall_64+0x6b/0x3a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-53035 since 06/09/2026. The exploitation is known to be difficult. There are known technical details, but no exploit is available.

Upgrading to version 6.1.175, 6.6.141, 6.12.91, 6.18.33 or 7.0.10 eliminates this vulnerability. Applying the patch bd3592129f24243713673a07225cf1f15a9bb835/3cef33b9813b78f227942572fb317afcd5c9ac94/87828b380956d4986f59f2c086e0b09b3e6cdaae/527057ebe8076dfbcaef51195ff1b7508646be2c/66d9fab4565eafe1afe7ba0581f79b76073b60fa/4d328dd695383224aa750ddee6b4ad40c0f8d205 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.174
• 6.6.140
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.12.70
• 6.12.71
• 6.12.72
• 6.12.73
• 6.12.74
• 6.12.75
• 6.12.76
• 6.12.77
• 6.12.78
• 6.12.79
• 6.12.80
• 6.12.81
• 6.12.82
• 6.12.83
• 6.12.84
• 6.12.85
• 6.12.86
• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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