Heap buffer overflow opening large email
Priority LOW 28CWE-122Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00277 20th percentileScored 2026-11-07
Fix Fixed Thunderbird (Mozilla): 140.17, 153.4, 157
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mozilla | Thunderbird | — | 140.17, 153.4, 157 | Patch available | CNA |
- Thunderbird VendorMozilla Affected — Fixed in 140.17, 153.4, 157 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 140.17.0; 141.0 to before 153.4.0; 154.0 to before 157.0 | Vulnerable | Mozilla |
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 140.17.0; 141.0 to before 153.4.0; 154.0 to before 157.0 Vulnerable ·Mozilla
Remediation
- Fix · CNA Thunderbird (Mozilla) Fixed in 140.17, 153.4, 157
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
Not affected: 3 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-103500
- 2026-10-03 Alias added: GHSA-vjxp-5j85-5rqg
- 2026-10-16 CVSS score added · NVD
- 2026-10-16 Weakness changed · NVD
- 2026-10-16 CVSS score added · CISA ADP
- 2026-10-16 Weakness changed · CISA ADP
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-26 Affected versions changed · Red Hat
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-2026-103500 · CVE Program
- CVE-2026-103500 · NVD
- FIRST EPSS
- GHSA-vjxp-5j85-5rqg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-103500 · 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