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Fencer Intel
low 2.5

CVE-2026-43864 json

mutt before 2.3.2 has a show_sig_summary NULL pointer dereference.

published 6mo ago modified 4mo ago also EUVD-2026-26904

cvss
2.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits
0
none known

Summary

mutt before 2.3.2 has a show_sig_summary NULL pointer dereference.

Patch / fix

  • mutt mutt 2.3.2
  • mutt Debian 13 2.2.13-1+deb13u1
  • mutt Debian 14 2.3.2-1

debian advisories DEBIAN-CVE-2026-43864

  • mutt SLES for SAP applications 16.0, SLES 16.0 2.2.16-160000.2.1

suse advisories SUSE-SU-2026:22340-1

  • mutt openSUSE Leap 16.0 2.2.16-160000.2.1

opensuse advisories openSUSE-SU-2026:21016-1

Is CVE-2026-43864 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-43864 updated cvss 4.7

mutt: Mutt: Denial of Service via null pointer dereference in show_sig_summary

  • Red Hat Enterprise Linux 6 mutt Red Hat Enterprise Linux 7 mutt Red Hat Enterprise Linux 8 mutt Red Hat Enterprise Linux 9 mutt Red Hat Enterprise Linux 10 mutt
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 2.5 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

Affected products

  • mutt mutt

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.