CVE-2022-1834: mozilla thunderbird Improper Certificate Validation
Vulnerability summary
CVE-2022-1834 is a medium (CVSS 6.5) Improper Certificate Validation vulnerability in mozilla thunderbird. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 31.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 12 · Related 3Timeline
- 22-12-2022PublishedVulnerability first disclosed.
- 16-04-2025Last modifiedVulnerability information updated.
Description
When displaying the sender of an email, and the sender name contained the Braille Pattern Blank space character multiple times, Thunderbird would have displayed all the spaces. This could have been used by an attacker to send an email message with the attacker's digital signature, that was shown with an arbitrary sender email address chosen by the attacker. If the sender name started with a false email address, followed by many Braille space characters, the attacker's email address was not visible. Because Thunderbird compared the invisible sender address with the signature's email address, if the signing key or certificate was accepted by Thunderbird, the email was shown as having a valid digital signature. This vulnerability affects Thunderbird < 91.10.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.39%
Chance of exploitation in the next 30 days
Percentile
31%
Versus all other CVEs
30-day change
+0.01 pp
From 0.38% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- thunderbird< 1:91.10.0-1
Mozilla1 product
- thunderbird≥ unspecified, < 91.10 | < 91.10
Ubuntu1 product
- thunderbird< 1:91.11.0+build2-0ubuntu0.18.04.1 | < 1:91.11.0+build2-0ubuntu0.20.04.1 | < 1:91.11.0+build2-0ubuntu0.22.04.1
3 vendors · 3 products
References
7 links- www.mozilla.org/security/advisories/mfsa2022-22/Vendor Advisory
