Double Free in Linux

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.

Vulnerability class: Double Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (5.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 5.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-43178: held from 0.001 to 0.002.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000

Affected products

  • Linux — versions 6.18.10, b9b97e6aeb534315f9646b2090d1a5024c6a4e82, 7.0
  • Linux Kernel — versions 6.19

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-43178?
CVE-2026-43178 is a high-severity vulnerability in Linux, classified under Double Free. CVSS score: 7.8/10. Published 2026-05-06.
How severe is CVE-2026-43178?
High severity. CVSS v3 base score is 7.8 out of 10.