CVE-2021-29969

MEDIUM
5.9
CVSS Score
Published: August 5, 2021 at 07:46 PM UTC
Updated: June 17, 2026 at 03:48 AM UTC
1 product affected across 1 vendorThunderbird

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Severity
MEDIUM5.9
Exploit prediction
EPSS 1%

Description

If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server responses prior to the completion of the STARTTLS handshake, then Thunderbird didn't ignore the injected data. This could have resulted in Thunderbird showing incorrect information, for example the attacker could have tricked Thunderbird to show folders that didn't exist on the IMAP server. This vulnerability affects Thunderbird < 78.12.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 78.12
Affected range stops below 78.12, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1682370
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
https://security.gentoo.org/glsa/202208-14

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-552

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