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Fencer Vulns
critical 9.8

CVE-2026-92238 json

Ambiguous parsing of mail headers

published 2026-09-15 54 d ago modified 2026-09-24 46 d ago also EUVD-2026-79242

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

Patch / fix

  • mozilla thunderbird 140.16, 153.3, 156
  • mozilla thunderbird_esr 140.16, 153.3, 156
  • thunderbird Debian 12 1:140.16.0esr-1~deb12u1
  • thunderbird Debian 13 1:140.16.0esr-1~deb13u1
  • thunderbird Debian 14 1:153.3.0esr-1

debian advisories DEBIAN-CVE-2026-92238

  • thunderbird RHEL 8 140.16.0-1.el8_10
  • thunderbird RHEL 10.2 140.16.0-1.el10_2
  • thunderbird RHEL 9 140.16.0-1.el9_8
  • thunderbird RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 140.16.0-1.el8_4
  • thunderbird RHEL 8.6 EUS_LONG_LIFE, RHEL 8.6 AUS 140.16.0-1.el8_6
  • thunderbird RHEL 9.6 EUS 140.16.0-1.el9_6
  • thunderbird RHEL 8.8 TUS, RHEL 8.8 E4S 140.16.0-1.el8_8
  • thunderbird RHEL 9.2 E4S 140.16.0-1.el9_2

red hat advisories RHSA-2026:82122RHSA-2026:81913RHSA-2026:81884RHSA-2026:81912RHSA-2026:81394RHSA-2026:81393

  • MozillaThunderbird SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 153.4.0-150400.13.6.1

suse advisories SUSE-SU-2026:4627-1

  • MozillaThunderbird openSUSE Tumbleweed 140.16.0-1.1

opensuse advisories openSUSE-SU-2026:11827-1

  • thunderbird AlmaLinux 8 140.16.0-1.el8_10.alma.1
  • thunderbird AlmaLinux 10 140.16.0-1.el10_2.alma.1
  • thunderbird AlmaLinux 9 140.16.0-1.el9_8.alma.1

almalinux advisories ALSA-2026:73971ALSA-2026:73130ALSA-2026:70642

  • thunderbird Rocky Linux 8 140.16.0-1.el8_10
  • thunderbird Rocky Linux 10 140.16.0-1.el10_2
  • thunderbird Rocky Linux 9 140.16.0-1.el9_8

rocky linux advisories RLSA-2026:73971RLSA-2026:73130RLSA-2026:70642

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-2026-92238 updated cvss 6.1

thunderbird: Thunderbird: Memory safety violations via maliciously crafted mail headers

  • Red Hat Enterprise Linux 6 thunderbird Red Hat Enterprise Linux 7 thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 rhel10/thunderbird-flatpak
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) thunderbird 140.16.0-1.el8_10
    fixed: vendor fix RHSA-2026:73971
  • Red Hat Enterprise Linux AppStream (v. 9) thunderbird 140.16.0-1.el9_8
    fixed: vendor fix RHSA-2026:70642
  • Red Hat Enterprise Linux AppStream (v. 10) thunderbird 140.16.0-1.el10_2
    fixed: vendor fix RHSA-2026:73130
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird 140.16.0-1.el8_4
    fixed: vendor fix RHSA-2026:82122
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird 140.16.0-1.el8_6
    fixed: vendor fix RHSA-2026:81913
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) thunderbird 140.16.0-1.el8_8
    fixed: vendor fix RHSA-2026:81912
show 7 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) thunderbird 140.16.0-1.el9_2
    fixed: vendor fix RHSA-2026:81394
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) thunderbird 140.16.0-1.el9_4
    fixed: vendor fix RHSA-2026:81393
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) thunderbird 140.16.0-1.el10_0
    fixed: vendor fix RHSA-2026:81392
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird 140.16.0-1.el9_6
    fixed: vendor fix RHSA-2026:81884
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) thunderbird 140.16.0-1.el8_4
    fixed: vendor fix RHSA-2026:82122
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) thunderbird 140.16.0-1.el8_6
    fixed: vendor fix RHSA-2026:81913
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) thunderbird 140.16.0-1.el8_8
    fixed: vendor fix RHSA-2026:81912

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
yes
Technical impact
total
Assessed
47 d ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Mozilla Thunderbird

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.