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Fencer Intel
medium 6.3

CVE-2025-3522 json

Leak of hashed Window credentials via crafted attachment URL

published last yr. modified 4mo ago also EUVD-2025-10965

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

Patch / fix

  • mozilla thunderbird 128.9.2, 137.0.2
  • mozilla thunderbird_esr 128.9.2, 137.0.2
  • thunderbird Debian 12 1:128.10.0esr-1~deb12u1
  • thunderbird Debian 14, Debian 13 1:128.10.0esr-1

debian advisories DEBIAN-CVE-2025-3522

  • thunderbird Ubuntu 22.04 LTS 1:128.12.0+build1-0ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2025-3522

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • thunderbird RHEL 10.0 128.10.0-1.el10_0
  • thunderbird RHEL 9 128.10.0-1.el9_6
  • thunderbird RHEL 8 128.9.2-1.el8_10
  • thunderbird RHEL 9 128.9.2-1.el9_5
  • thunderbird RHEL 8.6 TUS, RHEL 8.6 E4S, RHEL 8.6 AUS 128.9.2-1.el8_6
  • thunderbird RHEL 8.4 TUS, RHEL 8.4 E4S, RHEL 8.4 AUS 128.9.2-1.el8_4
  • thunderbird RHEL 8.8 EUS 128.9.2-1.el8_8
  • thunderbird RHEL 9.0 E4S 128.9.2-1.el9_0

red hat advisories RHSA-2025:7507RHSA-2025:7435RHSA-2025:4665RHSA-2025:4649RHSA-2025:4654RHSA-2025:4617

  • MozillaThunderbird SLE Workstation Extension 15 SP6, SLE Module for Package Hub 15 SP6, openSUSE Leap 15.6 128.9.2-150200.8.209.1

suse advisories SUSE-SU-2025:1366-1

  • MozillaThunderbird openSUSE Tumbleweed 128.9.2-1.1

opensuse advisories openSUSE-SU-2025:15000-1

  • thunderbird AlmaLinux 9 128.10.0-1.el9_6.alma.1
  • thunderbird AlmaLinux 10 128.10.0-1.el10_0.alma.1
  • thunderbird AlmaLinux 8 128.9.2-1.el8_10.alma.1
  • thunderbird AlmaLinux 9 128.9.2-1.el9_5.alma.1

almalinux advisories ALSA-2025:7435ALSA-2025:7507ALSA-2025:4649ALSA-2025:4229

  • thunderbird Rocky Linux 9 128.10.0-1.el9_5

rocky linux advisories RLSA-2025:7435

Is CVE-2025-3522 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.

Check with Fencer

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-2025-3522 updated cvss 7.4

thunderbird: Leak of hashed Window credentials via crafted attachment URL

  • Red Hat Enterprise Linux 6 thunderbird Red Hat Enterprise Linux 7 thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 thunderbird-flatpak-container Red Hat Enterprise Linux 10 thunderbird-flatpak-container
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) thunderbird 128.9.2-1.el8_10
    fixed: vendor fix RHSA-2025:4649
  • Red Hat Enterprise Linux AppStream (v. 9) thunderbird 128.9.2-1.el9_5, thunderbird 128.10.0-1.el9_6
    fixed: vendor fix RHSA-2025:4229
  • Red Hat Enterprise Linux AppStream (v. 10) thunderbird 128.10.0-1.el10_0
    fixed: vendor fix RHSA-2025:7507
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) thunderbird 128.9.2-1.el8_2
    fixed: vendor fix RHSA-2025:4389
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird 128.9.2-1.el8_4
    fixed: vendor fix RHSA-2025:4654
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird 128.9.2-1.el8_6
    fixed: vendor fix RHSA-2025:4665
show 8 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) thunderbird 128.9.2-1.el8_4
    fixed: vendor fix RHSA-2025:4654
  • Red Hat Enterprise Linux AppStream E4S (v.8.6) thunderbird 128.9.2-1.el8_6
    fixed: vendor fix RHSA-2025:4665
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) thunderbird 128.9.2-1.el9_0
    fixed: vendor fix RHSA-2025:4514
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) thunderbird 128.9.2-1.el8_8
    fixed: vendor fix RHSA-2025:4617
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) thunderbird 128.9.2-1.el9_2
    fixed: vendor fix RHSA-2025:4513
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) thunderbird 128.9.2-1.el9_4
    fixed: vendor fix RHSA-2025:4512
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) thunderbird 128.9.2-1.el8_4
    fixed: vendor fix RHSA-2025:4654
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) thunderbird 128.9.2-1.el8_6
    fixed: vendor fix RHSA-2025:4665

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
last yr.

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

Affected products

  • Mozilla Thunderbird

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

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.

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