CVE-2026-72183landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path
- 8.4HighCVSS base score
- 0.17%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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]
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 2 months later
· 2 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.4 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H |
| NVDNVD · Received | 3.1 | High8.4 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.17% · top 93% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.4.
Affected products
- affected 332facfa80751b80006c2f95b13c6d208ab0aee1 – < 7a92e9fd1d496a610b40e0c4253fd54e7496f5ab
- affected 18eb75f3af40be1f0fc2025d4ff821711222a2fd – < 1f18aac2637220b5847d073447498e81ddca10b2
- affected 18eb75f3af40be1f0fc2025d4ff821711222a2fd – < 04916f7dc6d37cd478b06c86398c34a6963ac8c9
- affected 18eb75f3af40be1f0fc2025d4ff821711222a2fd – < 4b80320ca7ed03d6e683f95b6066565dc97b9f92
- affected 6861348d863c0eaa4af67492d640a9644a829c59
- affected 0906a9685d7057aea982e970da3e1cf3e5aca68b
- affected 6.12.24 – < 6.12.101
- affected 6.13.12 – < 6.14
- affected 6.14.3 – < 6.15
- affected 6.15
- unaffected < 6.15
- unaffected 6.12.101 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References4
- https://git.kernel.org/stable/c/7a92e9fd1d496a610b40e0c4253fd54e7496f5ab (opens in a new tab)
- https://git.kernel.org/stable/c/1f18aac2637220b5847d073447498e81ddca10b2 (opens in a new tab)
- https://git.kernel.org/stable/c/04916f7dc6d37cd478b06c86398c34a6963ac8c9 (opens in a new tab)
- https://git.kernel.org/stable/c/4b80320ca7ed03d6e683f95b6066565dc97b9f92 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-58941 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-72183)Record last updated .