How severe is CVE-2026-42512?

CVE-2026-42512 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-42512 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42512?

CVE-2026-42512 primarily affects Freebsd. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-42512?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42512 have an EU (EUVD) identifier?

Yes. CVE-2026-42512 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26357.

When was CVE-2026-42512 published?

CVE-2026-42512 was published on 2026-04-30 and last updated on 2026-06-17.

CVE-2026-42512

CVE-2026-42512 is a high-severity vulnerability in Freebsd with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26357
Weakness: CWE-122
Affected product: Freebsd
Published: 2026-04-30
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-42512?: CVE-2026-42512 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-42512 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42512?: CVE-2026-42512 primarily affects Freebsd. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42512?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42512 have an EU (EUVD) identifier?: Yes. CVE-2026-42512 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26357.
When was CVE-2026-42512 published?: CVE-2026-42512 was published on 2026-04-30 and last updated on 2026-06-17.

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:15.dhclient.asc

Affected products (37)

cpe:2.3:o:freebsd:freebsd:13.5:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:beta3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p11:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p12:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p11:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.4:rc1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:*

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