CVE-2021-29956

Secret-key disclosure via lost import-time protection

Published Jun 24, 2021 · Updated Aug 3, 2024

Cleartext storage in Mozilla Thunderbird 78.8.1 through 78.10.1 allows attackers to read imported OpenPGP secret keys from local disk. The import path protects a password-protected key in RNP's temporary area, but loses that protection when exporting the key into permanent storage. Exposure requires an imported, password-protected secret key and local access to its profile; the flaw defeats master-password protection for that key.

CVSS severity4.3
Medium
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext storage in Mozilla Thunderbird 78.8.1 through 78.10.1 allows attackers to read imported OpenPGP secret keys from local disk. The import path protects a password-protected key in RNP's temporary area, but loses that protection when exporting the key into permanent storage. Exposure requires an imported, password-protected secret key and local access to its profile; the flaw defeats master-password protection for that key.

The record

CVE
CVE-2021-29956
Published
Jun 24, 2021
Updated
Aug 3, 2024
Vendor
Mozilla
Product
Thunderbird
Classifications
CWE-312, T1552.001
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <78.10.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Mozilla · Thunderbirdversion=unspecified <78.10.2

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-312Cleartext Storage of Sensitive Information
T1552.001Unsecured Credentials: Credentials In Files

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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