Vulnerability details
CVE-2026-14899
Off-by-one out of bounds read in MIME header parser for forwarding
CVSS 3.1
7.5High
Official description
The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CISA ADP / Vulnrichment (CISA-ADP) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| No product information recorded. | |||
References and advisories
3
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Details
- Published
- 2026-07-22
- Last updated
- 2026-07-27
- State
- Published
- Assigner (CNA)
- mozilla
Exploit prediction (EPSS)
0.46%
Probability of exploitation in 30 days
40.8%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-193Off-by-one Error