Linux Kernel up to 7.2.5 s390dbf debug_unregister deadlock

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4.0$0-$5k0.00

Summaryinfo

A vulnerability labeled as problematic has been found in Linux Kernel up to 7.2.5. This affects the function debug_unregister of the component s390dbf. Executing a manipulation can lead to deadlock. This vulnerability appears as CVE-2026-90209. The attack requires local access. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic was found in Linux Kernel up to 7.2.5. This vulnerability affects the function debug_unregister of the component s390dbf. The manipulation with an unknown input leads to a deadlock vulnerability. The CWE definition for the vulnerability is CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: s390/debug: Fix deadlock during unregister Unregistering an s390dbf debug area while one of the associated debugfs files is being written to can cause a deadlock: $ echo >.../vmur/level $ rmmod vmur =================================================== debugfs write debugfs_file_get() debug_unregister() mutex_lock(debug_mutex) debugfs_remove() wait for debugfs_file_put() debug_file_ops.write() debug_input() mutex_lock(debug_mutex) ==> DEADLOCK Fix this by splitting debug_unregister() into an s390dbf and debugfs part, and running only the s390dbf part with debug_mutex locked.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-90209 since 09/11/2026. The exploitation appears to be easy. Local access is required to approach this attack. Additional levels of successful authentication are necessary for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed/183f8f6d64bb0510070c856b9927618c53014a7b/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba/5d83f3faa3fb7f23f298cfd40382611999de5d1d/54e1259b75d6402a1d0cfb822b9bb2c507e53dab/445c31ac638fd1af203d79bdf25fc0cb3149fbbc is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.2
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.2
VulDB Temp Score: 4.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Deadlock
CWE: CWE-833 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed/183f8f6d64bb0510070c856b9927618c53014a7b/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba/5d83f3faa3fb7f23f298cfd40382611999de5d1d/54e1259b75d6402a1d0cfb822b9bb2c507e53dab/445c31ac638fd1af203d79bdf25fc0cb3149fbbc

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90209 (🔒)
GCVE (CVE): GCVE-0-2026-90209
GCVE (VulDB): GCVE-100-406738

Entryinfo

Created: 09/17/2026 20:50
Changes: 09/17/2026 20:50 (59)
Complete: 🔍
Cache ID: 216::103

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