Leak of hashed Window credentials via crafted attachment URL
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Partial Red Hat: 14 fixed, 4 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-601.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Thunderbird (Mozilla) Fixed in 128.9.2, 137.0.2
Red Hat 11 advisories
- RHSA-2025:7507 Released 2025-05-13 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 10) thunderbird-128.10.0-1.el10_0
- RHSA-2025:7435 Released 2025-05-13 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 9) thunderbird-128.10.0-1.el9_6
- RHSA-2025:4665 Released 2025-05-07 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird-128.9.2-1.el8_6
- Red Hat Enterprise Linux AppStream E4S (v.8.6) thunderbird-128.9.2-1.el8_6
- Red Hat Enterprise Linux AppStream TUS (v.8.6) thunderbird-128.9.2-1.el8_6
Show 8 more Red Hat advisories
- RHSA-2025:4654 Released 2025-05-07 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird-128.9.2-1.el8_4
- Red Hat Enterprise Linux AppStream E4S (v.8.4) thunderbird-128.9.2-1.el8_4
- Red Hat Enterprise Linux AppStream TUS (v.8.4) thunderbird-128.9.2-1.el8_4
- RHSA-2025:4649 Released 2025-05-07 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-128.9.2-1.el8_10
- RHSA-2025:4617 Released 2025-05-07 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.8.8) thunderbird-128.9.2-1.el8_8
- RHSA-2025:4514 Released 2025-05-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.9.0) thunderbird-128.9.2-1.el9_0
- RHSA-2025:4512 Released 2025-05-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.9.4) thunderbird-128.9.2-1.el9_4
- RHSA-2025:4513 Released 2025-05-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.9.2) thunderbird-128.9.2-1.el9_2
- RHSA-2025:4389 Released 2025-04-30 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v. 8.2) thunderbird-128.9.2-1.el8_2
- RHSA-2025:4229 Released 2025-04-28 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 9) thunderbird-128.9.2-1.el9_5
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2025:7507 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2025:4649 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2025:4229, RHSA-2025:7435 |
| Red Hat Enterprise Linux AppStream AUS (v. 8.2) | Fixed | RHSA-2025:4389 |
| Red Hat Enterprise Linux AppStream AUS (v.8.4) | Fixed | RHSA-2025:4654 |
| Red Hat Enterprise Linux AppStream AUS (v.8.6) | Fixed | RHSA-2025:4665 |
| Red Hat Enterprise Linux AppStream E4S (v.8.4) | Fixed | RHSA-2025:4654 |
| Red Hat Enterprise Linux AppStream E4S (v.8.6) | Fixed | RHSA-2025:4665 |
| Red Hat Enterprise Linux AppStream E4S (v.9.0) | Fixed | RHSA-2025:4514 |
| Red Hat Enterprise Linux AppStream EUS (v.8.8) | Fixed | RHSA-2025:4617 |
| Red Hat Enterprise Linux AppStream EUS (v.9.2) | Fixed | RHSA-2025:4513 |
| Red Hat Enterprise Linux AppStream EUS (v.9.4) | Fixed | RHSA-2025:4512 |
| Red Hat Enterprise Linux AppStream TUS (v.8.4) | Fixed | RHSA-2025:4654 |
| Red Hat Enterprise Linux AppStream TUS (v.8.6) | Fixed | RHSA-2025:4665 |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-3522
- 2026-10-03 Alias added: GHSA-78fw-w53r-pgwg
References
More Mozilla Thunderbird vulnerabilities
- TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
- TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
- TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
- TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
- TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
- TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2025-3522 · CVE Program
- CVE-2025-3522 · NVD
- FIRST EPSS
- GHSA-78fw-w53r-pgwg · GitHub Advisory Database · CC BY 4.0
- CVE-2025-3522 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences