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CVE-2025-26695VulnerabilityPublished Updated

CVE-2025-26695: Mozilla Thunderbird · Vulnerability

Affects Mozilla ThunderbirdSource CVE Database V5

0

Not known to be exploited · CVSS 5.3 Medium : upgrade to 128.8 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 128.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade Mozilla Thunderbird to 128.8.

Affected software

ProductAffectedFixed in
Mozilla ThunderbirdAffected
  • <128.8
Fixed in
  • 128.8

AI-suggested

This vulnerability has been fixed in Mozilla Thunderbird versions 136 and 128.8 (ESR). Users and administrators should upgrade to these versions or later to remediate the issue. The vendor advisories from Mozilla confirm that the flaw is addressed in these releases. No additional mitigation steps are required beyond applying the official updates.

Description

When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

References

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