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TI-2021-10586 Aliases CVE-2021-29969GHSA-ggp3-c9px-5c4p

If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker…

Priority LOW 29CWE-552Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
High · None · None
Fix status
Partial Red Hat: 6 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-552.

Summary

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.

Why it matters now

EPSS 0.012 68th percentileScored 2026-11-07
Fix Partial Thunderbird (Mozilla): 78.12Red Hat: 4 advisoriesRed Hat: 6 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaThunderbirdbefore 78.1278.12Patch availableCNA
  • Thunderbird VendorMozilla Affected before 78.12 Fixed in 78.12 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.12VulnerableMozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.12 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.12

Red Hat 4 advisories

  • RHSA-2021:2914 Released 2021-07-27 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.12.0-2.el8_2
  • RHSA-2021:2881 Released 2021-07-26 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.12.0-2.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.12.0-2.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.12.0-2.el7_9
  • RHSA-2021:2883 Released 2021-07-26 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.12.0-3.el8_4
Show 1 more Red Hat advisories
  • RHSA-2021:2882 Released 2021-07-26 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.12.0-2.el8_1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Mozilla Thunderbird 78.12

    3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2021-10593 Out-of-bounds write in Mozilla ThunderbirdPriority MEDIUM 41
    • TI-2021-10587 Use after free in Mozilla ThunderbirdPriority MEDIUM 41
    Show all 3 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:2883
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:2882
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:2914
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:2881
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:2881
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:2881

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-29969
  2. 2026-10-03 Alias added: GHSA-ggp3-c9px-5c4p

References

Advisory 3

  • TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
  • TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
  • TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
  • TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
See all 2067 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences