Linux Kernel up to 6.18.17/6.19.6/7.0-rc1/7.0-rc2 libata privilege escalation

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.16

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.17/6.19.6/7.0-rc1/7.0-rc2. It has been declared as critical. This affects an unknown function of the component libata. Executing a manipulation can lead to an unknown weakness. This vulnerability is handled as CVE-2026-23355. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.17/6.19.6/7.0-rc1/7.0-rc2. It has been declared as critical. This vulnerability affects some unknown processing of the component libata. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ata: libata: cancel pending work after clearing deferred_qc Syzbot reported a WARN_ON() in ata_scsi_deferred_qc_work(), caused by ap->ops->qc_defer() returning non-zero before issuing the deferred qc. ata_scsi_schedule_deferred_qc() is called during each command completion. This function will check if there is a deferred QC, and if ap->ops->qc_defer() returns zero, meaning that it is possible to queue the deferred qc at this time (without being deferred), then it will queue the work which will issue the deferred qc. Once the work get to run, which can potentially be a very long time after the work was scheduled, there is a WARN_ON() if ap->ops->qc_defer() returns non-zero. While we hold the ap->lock both when assigning and clearing deferred_qc, and the work itself holds the ap->lock, the code currently does not cancel the work after clearing the deferred qc. This means that the following scenario can happen: 1) One or several NCQ commands are queued. 2) A non-NCQ command is queued, gets stored in ap->deferred_qc. 3) Last NCQ command gets completed, work is queued to issue the deferred qc. 4) Timeout or error happens, ap->deferred_qc is cleared. The queued work is currently NOT canceled. 5) Port is reset. 6) One or several NCQ commands are queued. 7) A non-NCQ command is queued, gets stored in ap->deferred_qc. 8) Work is finally run. Yet at this time, there is still NCQ commands in flight. The work in 8) really belongs to the non-NCQ command in 2), not to the non-NCQ command in 7). The reason why the work is executed when it is not supposed to, is because it was never canceled when ap->deferred_qc was cleared in 4). Thus, ensure that we always cancel the work after clearing ap->deferred_qc. Another potential fix would have been to let ata_scsi_deferred_qc_work() do nothing if ap->ops->qc_defer() returns non-zero. However, canceling the work when clearing ap->deferred_qc seems slightly more logical, as we hold the ap->lock when clearing ap->deferred_qc, so we know that the work cannot be holding the lock. (The function could be waiting for the lock, but that is okay since it will do nothing if ap->deferred_qc is not set.)

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-23355 since 01/13/2026. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 03/30/2026).

The vulnerability scanner Nessus provides a plugin with the ID 304116 (Linux Distros Unpatched Vulnerability : CVE-2026-23355), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.18, 6.19.7, 7.0-rc1 or 7.0-rc3 eliminates this vulnerability. Applying the patch 0d12453818c35e1ded84633152c6b05002ae48b9/6c5e8f16b5e8e614e829aaf38619bdd79107bb0a/58e658763ba2aa9168d8516b98a6314d7461a53e/aac9b27f7c1f2b2cf7f50a9ca633ecbbcaf22af9 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (304116). Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 304116
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-23355

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.18/6.19.7/7.0-rc1/7.0-rc3
Patch: 0d12453818c35e1ded84633152c6b05002ae48b9/6c5e8f16b5e8e614e829aaf38619bdd79107bb0a/58e658763ba2aa9168d8516b98a6314d7461a53e/aac9b27f7c1f2b2cf7f50a9ca633ecbbcaf22af9

Timelineinfo

01/13/2026 CVE reserved
03/25/2026 +71 days Advisory disclosed
03/25/2026 +0 days VulDB entry created
03/30/2026 +5 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-23355 (🔒)
GCVE (CVE): GCVE-0-2026-23355
GCVE (VulDB): GCVE-100-353086

Entryinfo

Created: 03/25/2026 13:29
Updated: 03/30/2026 10:38
Changes: 03/25/2026 13:29 (57), 03/28/2026 10:23 (2), 03/30/2026 10:38 (1)
Complete: 🔍
Cache ID: 216:926:103

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