NVD / CVE Program· CNA mozilla

CVE-2021-29956: OpenPGP secret keys that were imported using Thunderbird version 78.8.1 up to version 78.10.1 were stored unencrypted on the user's local…

MediumCVSS 4.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 17/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.81% (FIRST EPSS); higher than 57.3% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
Fixed version: thunderbird (Alpine:v3.16) 91.3.2-r0; thunderbird (Debian:10) 1:78.11.0-1~deb10u1; thunderbird (Debian:12) 1:78.10.2-1.
Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to thunderbird (Alpine:v3.16) 91.3.2-r0; thunderbird (Debian:10) 1:78.11.0-1~deb10u1; thunderbird (Debian:12) 1:78.10.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

OpenPGP secret keys that were imported using Thunderbird version 78.8.1 up to version 78.10.1 were stored unencrypted on the user's local disk. The master password protection was inactive for those keys. Version 78.10.2 will restore the protection mechanism for newly imported keys, and will automatically protect keys that had been imported using affected Thunderbird versions. This vulnerability affects Thunderbird < 78.10.2.

Pre-auth

Published: Jun 24, 2021
Updated: Jun 16, 2026
EPSS: 0.8% · 57th percentile
CWE: CWE-312

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 17 / 40 · 4.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.8%

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
mozilla	thunderbird	cpe:2.3:a:mozilla:thunderbird

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.

Mozilla Thunderbird
- unspecified and later · before 78.10.2affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

mozilla thunderbird78.8.1 and later · up to 78.10.1 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Alpine:v3.16	thunderbird	from 78.8.1 · before 91.3.2-r0	91.3.2-r0
Debian:10	thunderbird	before 1:78.11.0-1~deb10u1	1:78.11.0-1~deb10u1
Debian:12	thunderbird	before 1:78.10.2-1	1:78.10.2-1
Debian:9	thunderbird	before 1:78.11.0-1~deb9u1	1:78.11.0-1~deb9u1
openSUSE:Leap 15.3	MozillaThunderbird	before 78.10.2-8.27.1	78.10.2-8.27.1
Red Hat:enterprise_linux:7::client	thunderbird	before 0:78.11.0-1.el7_9	0:78.11.0-1.el7_9
Red Hat:enterprise_linux:7::client	thunderbird-debuginfo	before 0:78.11.0-1.el7_9	0:78.11.0-1.el7_9
Red Hat:enterprise_linux:8::appstream	thunderbird	before 0:78.11.0-1.el8_4	0:78.11.0-1.el8_4
Red Hat:enterprise_linux:8::appstream	thunderbird-debuginfo	before 0:78.11.0-1.el8_4	0:78.11.0-1.el8_4
Red Hat:enterprise_linux:8::appstream	thunderbird-debugsource	before 0:78.11.0-1.el8_4	0:78.11.0-1.el8_4
Red Hat:rhel_eus:8.1::appstream	thunderbird	before 0:78.11.0-1.el8_1	0:78.11.0-1.el8_1
Red Hat:rhel_eus:8.1::appstream	thunderbird-debuginfo	before 0:78.11.0-1.el8_1	0:78.11.0-1.el8_1
Red Hat:rhel_eus:8.1::appstream	thunderbird-debugsource	before 0:78.11.0-1.el8_1	0:78.11.0-1.el8_1
Red Hat:rhel_eus:8.2::appstream	thunderbird	before 0:78.11.0-1.el8_2	0:78.11.0-1.el8_2
Red Hat:rhel_eus:8.2::appstream	thunderbird-debuginfo	before 0:78.11.0-1.el8_2	0:78.11.0-1.el8_2
Red Hat:rhel_eus:8.2::appstream	thunderbird-debugsource	before 0:78.11.0-1.el8_2	0:78.11.0-1.el8_2
Rocky Linux:8	thunderbird	before 0:78.11.0-1.el8_4	0:78.11.0-1.el8_4
SUSE:Linux Enterprise Workstation Extension 15 SP2	MozillaThunderbird	before 78.10.2-8.27.1	78.10.2-8.27.1

Same product

mozilla: all records

Other highest-scoring records for the same primary product.

CVE-2019-11705A flaw in Thunderbird's implementation of iCal causes a stack buffer overflow in icalrecur_add_bydayrules when processing certain email…
42Plan
CVE-2019-11704A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in icalmemory_strdup_and_dequote when processing certain email…
42Plan
CVE-2019-11703A flaw in Thunderbird's implementation of iCal causes a heap buffer overflow in parser_get_next_char when processing certain email…
42Plan

Published before and after this one in the same product

← EarlierCVE-2021-29949Jun 24, 2021 · When loading the shared library that provides the OTR protocol implementation, Thunderbird will initially attempt to open it using a…
31Monitor
← EarlierCVE-2021-29950Jun 24, 2021 · Thunderbird unprotects a secret OpenPGP key prior to using it for a decryption, signing or key import task.
30Monitor
Later →CVE-2021-29957Jun 24, 2021 · If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part…
17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
alpine:thunderbird	91.3.2-r0 · Alpine:v3.16	Package registry (OSV)
debian:thunderbird	1:78.10.2-1 · Debian:12	Package registry (OSV)
opensuse:MozillaThunderbird	78.10.2-8.27.1 · openSUSE:Leap 15.3	Package registry (OSV)
red hat:thunderbird	0:78.11.0-1.el8_2 · Red Hat:rhel_eus:8.2::appstream	Package registry (OSV)
red hat:thunderbird-debuginfo	0:78.11.0-1.el8_2 · Red Hat:rhel_eus:8.2::appstream	Package registry (OSV)
red hat:thunderbird-debugsource	0:78.11.0-1.el8_2 · Red Hat:rhel_eus:8.2::appstream	Package registry (OSV)
rocky linux:thunderbird	0:78.11.0-1.el8_4 · Rocky Linux:8	Package registry (OSV)
suse:MozillaThunderbird	78.10.2-8.27.1 · SUSE:Linux Enterprise Workstation Extension 15 SP2	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.