CVE-2026-92239
HIGH 8.1 ALL-YEARSA maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
ELEVATED IMPACT
Severe if exploited (CVSS 8.1), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 33rd percentile
○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no
Impact if exploited
8.1CVSS 3.1 · HIGH · ADP
- ConfidentialityHigh
- IntegrityNone
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.
Weakness (CWE)
- CWE-125: Out-of-bounds Read
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Mozilla | Thunderbird | < 140.16.0 |
| Mozilla | Thunderbird | ≥ 141.0 and < 153.3.0 |
| Mozilla | Thunderbird | ≥ 154.0 and < 156.0 |
All CVSS metrics
- HIGH 8.1 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H - HIGH 8.1 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H