How severe is CVE-2026-72183?

No CVSS score has been assigned to CVE-2026-72183 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-72183?

CVE-2026-72183 affects the following packages: Kernel (Linux). Ecosystems affected: Linux.

How do I fix CVE-2026-72183?

Update Kernel to 6.12.101 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-72183 is resolved across your whole dependency graph.

How do I detect CVE-2026-72183 in my Linux dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-72183 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-72183?

O3 pinpoints whether CVE-2026-72183 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-72183 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-72183 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-72183 published, and has it been updated?

CVE-2026-72183 was published on August 15, 2026 and was last updated on August 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐧 Linux

Not in CISA KEV

CVE-2026-72183

CVE-2026-72183 is a security vulnerability in Kernel. O3 Security confirms whether CVE-2026-72183 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path

Published

Aug 15, 2026

Updated

Aug 16, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 16, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐧Kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.

Description

In the Linux kernel, the following vulnerability has been resolved:

landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path

LANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling processes outside its Landlock domain. It can be bypassed through the asynchronous SIGIO delivery path.

A sandboxed process that owns any file or socket can arm it with fcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so that an I/O event makes the kernel deliver the chosen signal to the whole process group. As the head of its process group's task list (the default position right after fork()) that group can also hold the non-sandboxed process that launched it, e.g. a supervisor or a security monitor. The sandbox can thus kill or signal the processes LANDLOCK_SCOPE_SIGNAL is meant to protect from it.

The scope is enforced in hook_file_send_sigiotask() against the Landlock domain recorded at F_SETOWN time, not the live domain of the sender. control_current_fowner() decides whether to record that domain and skips recording it when the fowner target is in the caller's thread group, which is safe only for a single-task target (PIDTYPE_PID, PIDTYPE_TGID). For a process group (PIDTYPE_PGID) pid_task() returns only one member; recording is skipped whenever that member shares the caller's thread group, and hook_file_send_sigiotask() then lets the signal fan out to the whole group unchecked.

Record the domain for every non single-process target so the scope is enforced against each group member at delivery time.

That recording is necessary but not sufficient on its own: the kernel signals a process group through its members' thread-group leaders, and the leader of the registrant's own process can carry a different Landlock domain than the sibling thread that armed the owner. domain_is_scoped() would then deny that leader, even though commit 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") requires same-process delivery to be allowed. hook_task_kill() avoids this by evaluating same_thread_group() live, per recipient; the SIGIO path instead delegates the whole decision to a single registration-time check, which a process-group fan-out cannot honor.

So also record the registrant's thread group next to its domain and exempt it at delivery: hook_file_send_sigiotask() allows the signal whenever the recipient belongs to the registrant's own process, restoring the same-process guarantee while keeping out-of-domain group members blocked. The direct kill() path (hook_task_kill) already evaluates the live domain and is unaffected.

[mic: Check pid_type earlier and improve comment, fix commit message, fix comment formatting]

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐧Linux	`Kernel`	≥ 6.13.0&&< 6.12.101	6.12.101

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 6.12.101 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-72183 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-72183 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-72183. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In the Linux kernel, the following vulnerability has been resolved: landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path LANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling processes outside its Landlock domain. It can be bypassed through the asynchronous SIGIO delivery path. A sandboxed process that owns any file or socket can arm it with fcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so that an I/O event makes the kernel deliver the chosen signal to the whole process group. As the head of its process group's task list (the default positio

O3 Security · Impact-Aware SCA

Is CVE-2026-72183 in your dependencies?

O3 detects CVE-2026-72183 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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