Security readout for executives and security teams
Plain-English summary
Thunderbird could leave imported OpenPGP secret keys unencrypted on a user's local disk. If an attacker, malware, or unauthorized insider could read that disk or profile backups, private email encryption or signing keys might be exposed. Mozilla says Thunderbird 78.10.2 restores protection and protects keys imported by affected versions.
Executive priority
Prioritize remediation for users who rely on Thunderbird OpenPGP for sensitive communications. This is not described as remotely exploitable, but private key exposure can undermine confidentiality and trust in signed email.
Technical view
OpenPGP secret keys imported with Thunderbird 78.8.1 through 78.10.1 were stored unencrypted because master password protection was inactive for those keys. The CVE states Thunderbird versions before 78.10.2 are affected. Version 78.10.2 restores protection for new imports and automatically protects previously affected imported keys.
Likely exposure
Organizations are most likely exposed where users ran Thunderbird 78.8.1 through 78.10.1 and imported OpenPGP secret keys. Exposure is endpoint and profile-data focused, including local disks and backups, not a remotely reachable service.
Exploitation context
The provided sources do not report active exploitation, and CISA KEV status is false. Practical abuse depends on access to the user's local disk, Thunderbird profile, or backups containing the unencrypted secret keys.
Researcher notes
Evidence is limited to Mozilla and CVE records. The key facts are affected import window, unencrypted local storage, inactive master password protection, and automatic protection in 78.10.2. No CVSS, CWE, or public exploitation evidence is provided in the bundle.
Mitigation direction
- Upgrade Thunderbird to 78.10.2 or later.
- Confirm affected users have restarted Thunderbird after updating.
- Follow Mozilla guidance for OpenPGP key handling.
- Restrict access to Thunderbird profiles and endpoint backups.
- Assess whether exposed private keys need rotation or revocation.
Validation and detection
- Inventory Thunderbird versions on managed endpoints.
- Identify users who imported OpenPGP secret keys during affected versions.
- Confirm Thunderbird is now 78.10.2 or later.
- Review endpoint or backup access for exposed profile data.
- Document any key rotation or revocation decisions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Credential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-29956 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.mozilla.org/security/advisories/mfsa2021-22/CVE reference · x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1710290CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.