CVE-2026-92240

CRITICALCVSS 9.1/10EPSS 0.66%

Last modified

CVE-2026-92240 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. EPSS estimates a 0.66% chance of exploitation in the next 30 days.

Description

A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

Metrics

EPSS Probability
0.66%

50.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
MozillaThunderbird< 140.16.0
MozillaThunderbird>= 141.0, < 153.3.0
MozillaThunderbird>= 154.0, < 156.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-92240?
A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
How severe is CVE-2026-92240?
CVE-2026-92240 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.66% probability of exploitation in the next 30 days.
How do I fix CVE-2026-92240?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST