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Fencer Vulns
high 8.6

CVE-2026-110249 json

Denial-of-service in the Exchange email component

published 2026-10-13 26 d ago modified 2026-10-21 18 d ago also EUVD-2026-99208

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.

Patch / fix

  • mozilla thunderbird 153.5, 158
  • mozilla thunderbird_esr 153.5, 158
  • thunderbird Debian 12 1:153.5.1esr-1~deb12u1
  • thunderbird Debian 13 1:153.5.1esr-1~deb13u1
  • thunderbird Debian 14 1:153.5.0esr-1

debian advisories DEBIAN-CVE-2026-110249

  • MozillaThunderbird SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 153.5.0-150400.13.9.1

suse advisories SUSE-SU-2026:4736-1

  • MozillaThunderbird openSUSE Tumbleweed 153.5.1-1.1

opensuse advisories openSUSE-SU-2026:12224-1

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-2026-110249 updated cvss 3.4

thunderbird: Denial-of-service in the Exchange email component

  • Red Hat Enterprise Linux 6 thunderbird Red Hat Enterprise Linux 7 thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 thunderbird Red Hat Enterprise Linux 9 thunderbird Red Hat Enterprise Linux 10 thunderbird
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 10 rhel10/thunderbird-flatpak
    not affected: vulnerable code not present

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
total
Assessed
19 d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.6 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CNA 3.1 8.6 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected products

  • Mozilla Thunderbird

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.