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TI-2021-06310 Aliases CVE-2021-23991GHSA-x5j6-p8w8-5r65

If a Thunderbird user has previously imported Alice's OpenPGP key, and Alice has extended…

Priority LOW 32Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
High · High · 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.

Summary

If a Thunderbird user has previously imported Alice's OpenPGP key, and Alice has extended the validity period of her key, but Alice's updated key has not yet been imported, an attacker may send an email containing a crafted version of Alice's key with an invalid subkey, Thunderbird might subsequently attempt to use the invalid subkey, and will fail to send encrypted email to Alice. This vulnerability affects Thunderbird < 78.9.1.

Why it matters now

EPSS 0.01035 64th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Thunderbird (Mozilla): 78.9.1Red 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 78.9.178.9.1Patch availableCNA
  • Thunderbird VendorMozilla Affected before 78.9.1 Fixed in 78.9.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.9.1VulnerableMozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.9.1 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.9.1

Red Hat 4 advisories

  • RHSA-2021:1201 Released 2021-04-14 · Red Hat rating Moderate
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.9.1-1.el8_2
  • RHSA-2021:1192 Released 2021-04-14 · Red Hat rating Moderate
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.9.1-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.9.1-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.9.1-1.el7_9
  • RHSA-2021:1193 Released 2021-04-14 · Red Hat rating Moderate
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.9.1-1.el8_3
Show 1 more Red Hat advisories
  • RHSA-2021:1190 Released 2021-04-14 · Red Hat rating Moderate
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.9.1-1.el8_1

Fixed in the same release

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

  • Release ·

    Mozilla Thunderbird 78.9.1

    4 records Highest priority Priority LOW 4 LOW

    Other records, highest priority first

    • TI-2021-10566 Uncontrolled search path in Mozilla ThunderbirdPriority LOW 34
    • TI-2021-06312 Improper signature verification in Mozilla ThunderbirdPriority LOW 29
    • TI-2021-06311 Improper signature verification in Mozilla ThunderbirdPriority LOW 21
    Show all 4 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. 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-2021:1193
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:1190
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:1201
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:1192
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:1192
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:1192

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-23991
  2. 2026-10-03 Alias added: GHSA-x5j6-p8w8-5r65

References

Exploit 1

Advisory 1

  • 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