Linux Kernel up to 6.12.74/6.18.15/6.19.5 procfs mmput buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.12.74/6.18.15/6.19.5. This issue affects the function mmput of the component procfs. The manipulation results in buffer overflow. This vulnerability is cataloged as CVE-2026-43178. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.74/6.18.15/6.19.5. It has been classified as critical. Affected is the function mmput of the component procfs. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: procfs: fix possible double mmput() in do_procmap_query() When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY we return with -ENAMETOOLONG error. After recent changes this condition happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(), so original goto out is now wrong and will double-mmput() mm_struct. Fix by jumping further to clean up only vm_file and name_buf.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-43178 since 05/01/2026. The exploitability is told to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/02/2026).

The vulnerability scanner Nessus provides a plugin with the ID 318589 (Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.75, 6.18.16 or 6.19.6 eliminates this vulnerability. Applying the patch f9fe092084cd04deea18747f58a2304026e76aaa/8adaff87db143583e08eec4f4e7788f1ef8af94d/90f5e87c9b75833b9ef3a4415b92c0247f28ab2f/61dc9f776705d6db6847c101b98fa4f0e9eb6fa3 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 (318589). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

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

NVD Base Score: 7.8
NVD Vector: 🔒

CNA Base Score: 7.8
CNA Vector (Linux): 🔒

CVSSv2info

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 318589
Nessus Name: Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.75/6.18.16/6.19.6
Patch: f9fe092084cd04deea18747f58a2304026e76aaa/8adaff87db143583e08eec4f4e7788f1ef8af94d/90f5e87c9b75833b9ef3a4415b92c0247f28ab2f/61dc9f776705d6db6847c101b98fa4f0e9eb6fa3

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
07/02/2026 +57 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43178 (🔒)
GCVE (CVE): GCVE-0-2026-43178
GCVE (VulDB): GCVE-100-361464

Entryinfo

Created: 05/06/2026 16:49
Updated: 07/02/2026 19:00
Changes: 05/06/2026 16:49 (59), 06/04/2026 14:29 (2), 07/02/2026 19:00 (20)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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