Linux KernelOperating system · Linux
CVE-2026-53035
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA deadlock vulnerability exists in the Linux kernel's BPF sockmap functionality where bpf_iter_unix_seq_show() acquires a socket lock via lock_sock_fast() in the fast path, and if the iterator program attempts to update a sockmap via sock_map_update_elem(), it attempts to acquire the same lock again through bh_lock_sock(), causing a recursive locking deadlock with spin waiting.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 5.15, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed kernel versionRun 'uname -r' to get the kernel version, then compare it against affected ranges: 5.15 to < 6.1.175, 6.2 to < 6.6.141, 6.7 to < 6.12.91, 6.13 to < 6.18.33, or 6.19 to < 7.0.10Affected if The kernel version falls within any of the affected ranges listed in the CVE
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Verify BPF is enabledCheck for BPF support by looking for /sys/kernel/debug/tracing/events/bpf/ or running 'lsmod | grep bpf' to see if BPF modules are loadedAffected if BPF is not compiled or loaded, the attack surface does not exist
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Check for existing sockmapsList sockmap entries via 'sudo cat /proc/net/sockmap' or check for BPF maps of type BPF_MAP_TYPE_SOCKMAP using 'bpftool map show'Affected if No sockmaps exist in the system, the specific deadlock condition cannot be triggered
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Identify BPF iterator programs accessing AF_UNIX socketsReview BPF programs loaded in the kernel using 'bpftool prog show' and check for iter programs that may iterate over unix sockets while simultaneously updating sockmaps via sock_map_update_elem()Affected if BPF iterator programs simultaneously read AF_UNIX sockets and update sockmaps, triggering the recursive lock condition
You are affected if your kernel version is within the affected ranges AND BPF with sockmap functionality is actively in use with iterator programs that combine unix socket iteration and sockmap updates.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.1.1756.6.1416.12.91
Apply the kernel patch that adds proper lock nesting notation or restructures the locking in bpf_iter_unix_seq_show() to prevent the recursive lock acquisition. Until patched, avoid running BPF iter programs that simultaneously read AF_UNIX sockets and update sockmaps.
Linux kernel 6.1.175, 6.6.141, 6.12.91, or 6.18.33 (depending on which major version branch you are on)
- Check current kernel version using 'uname -r'
- Identify which version range your current kernel falls into based on the affected versions list
- Upgrade the Linux kernel to one of the fixed versions: 6.1.175 or later (for 6.1.x), 6.6.141 or later (for 6.2-6.6.x), 6.12.91 or later (for 6.7-6.12.x), or 6.18.33 or later (for 6.13-6.18.x)
- Reboot the system to load the new kernel
- Verify the fix by running the same BPF sockmap test that triggered the deadlock, or confirm using 'modinfo' that the bpf and sockmap modules are loaded correctly
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-53035 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-53035 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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