Linux Kernel up to 6.12.100/6.18.39/7.1.4 landlock hook_file_send_sigiotask sandbox

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8.4	$0-$5k	0.50-

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.100/6.18.39/7.1.4. It has been classified as very critical. This affects the function hook_file_send_sigiotask of the component landlock. This manipulation causes sandbox. This vulnerability is registered as CVE-2026-72183. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.100/6.18.39/7.1.4. It has been declared as very critical. Affected by this vulnerability is the function hook_file_send_sigiotask of the component landlock. The manipulation with an unknown input leads to a sandbox vulnerability. The CWE definition for the vulnerability is CWE-265. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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]

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-72183 since 08/09/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026). The attack technique deployed by this issue is T1611 according to MITRE ATT&CK.

Upgrading to version 6.12.101, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 7a92e9fd1d496a610b40e0c4253fd54e7496f5ab/1f18aac2637220b5847d073447498e81ddca10b2/04916f7dc6d37cd478b06c86398c34a6963ac8c9/4b80320ca7ed03d6e683f95b6066565dc97b9f92 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8
• 6.9
• 6.10
• 6.11
• 6.12.100
• 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
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Sandbox
CWE: CWE-265 / CWE-264
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.101/6.18.40/7.1.5/7.2-rc1
Patch: 7a92e9fd1d496a610b40e0c4253fd54e7496f5ab/1f18aac2637220b5847d073447498e81ddca10b2/04916f7dc6d37cd478b06c86398c34a6963ac8c9/4b80320ca7ed03d6e683f95b6066565dc97b9f92

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72183 (🔒)
GCVE (CVE): GCVE-0-2026-72183
GCVE (VulDB): GCVE-100-390535

Entryinfo

Created: 08/15/2026 12:28
Changes: 08/15/2026 12:28 (59)
Complete: 🔍
Cache ID: 216::103

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Discussion

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