Buffer overflow in FreeBSD

CVE-2026-42512

As dhclient is building an environment to pass to dhclient-script, it may need to resize the array of string pointers. The code which expands the array incorrectly calculates its new size when requesting memory, resulting in a heap buffer overrun. A specially crafted packet can cause dhclient to overrun its buffer of environment entries. This can result in a crash, but it may be possible to leverage this bug to achieve remote code execution.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.018 (77.8th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 77.8% 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-2026-42512: held from 0.014 to 0.018.

EPSS over last 30 days · oldest: 0.014 · newest: 0.018 · change: +0.004

Affected products

  • FreeBSD — versions 14.3, 13.5, 15.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42512?
CVE-2026-42512 is a high-severity vulnerability in FreeBSD, classified under Heap-based Buffer Overflow. CVSS score: 8.1/10. Published 2026-04-30.
How severe is CVE-2026-42512?
High severity. CVSS v3 base score is 8.1 out of 10.