How severe is CVE-2026-43859?

CVE-2026-43859 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-43859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-43859 have an EU (EUVD) identifier?

Yes. CVE-2026-43859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26895.

When was CVE-2026-43859 published?

CVE-2026-43859 was published on 2026-05-04 and last updated on 2026-06-17.

CVE-2026-43859

CVE-2026-43859 is a low-severity vulnerability with a CVSS 3.x base score of 3.7. 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-158.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26895
Weakness: CWE-158
Published: 2026-05-04
Last modified: 2026-06-17

Description

mutt before 2.3.2 sometimes uses strfcpy instead of memcpy for the IMAP auth_cram MD5 digest.

Frequently asked questions

What is CVE-2026-43859?: mutt before 2.3.2 sometimes uses strfcpy instead of memcpy for the IMAP auth_cram MD5 digest.
How severe is CVE-2026-43859?: CVE-2026-43859 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-43859 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-43859?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-43859 have an EU (EUVD) identifier?: Yes. CVE-2026-43859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26895.
When was CVE-2026-43859 published?: CVE-2026-43859 was published on 2026-05-04 and last updated on 2026-06-17.

References

https://github.com/muttmua/mutt/commit/834c5a2ed0479e51e8662a31caed129f136f4805

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