VulnerabilityPublished 27 Oct 2026

CVE-2026-118174: Mozilla Thunderbird · Displaying a message could load an attacker-chosen URL through an OpenPGP key attachment

Affects Mozilla ThunderbirdSource CVE Database V5

Not known to be exploited · fixed in 153.6 : patch Mozilla Thunderbird soon.

Data as of 27 Oct 2026, 18:57 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in 153.6

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

This vulnerability is fixed in Thunderbird version 159. Users should update to Thunderbird 159 or later to remediate this issue. No additional mitigation actions are required once the update is applied.

Description

When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Impact

The vulnerability allows an attacker to bypass Thunderbird's remote content blocking by loading attacker-chosen URLs automatically when displaying messages with OpenPGP key attachments. On Windows, this can lead to leakage of NTLM credentials to attacker-controlled network shares, potentially enabling offline password cracking or relay attacks. On other operating systems, the impact is limited to bypassing remote content blocking without credential leakage.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 27 Oct 2026, 18:42 UTC

Technical details

References

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