CVE-2026-43178

Description

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.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-415 CWE-415

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.12.70 — 6.12.75
linux	linux_kernel	6.18.10 — 6.18.16
linux	linux_kernel	6.19.1 — 6.19.6
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/61dc9f776705d6db6847c101b98fa4f0e9eb6fa3 https://git.kernel.org/stable/c/8adaff87db143583e08eec4f4e7788f1ef8af94d https://git.kernel.org/stable/c/90f5e87c9b75833b9ef3a4415b92c0247f28ab2f https://git.kernel.org/stable/c/f9fe092084cd04deea18747f58a2304026e76aaa

Frequently Asked Questions

What is CVE-2026-43178? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-43178? +

CVE-2026-43178 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43178? +

CVE-2026-43178 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43178? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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