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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mozilla | Thunderbird | affected |
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Advisories
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Fixes
Solution
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Workaround
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References
History
Wed, 22 Jul 2026 20:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Off-by-one out of bounds read in MIME header parser for forwarding | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: mozilla
Published:
Updated: 2026-07-22T19:19:42.305Z
Reserved: 2026-07-06T19:53:12.713Z
Link: CVE-2026-14899
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
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