TI-2021-16098 Aliases CVE-2021-38498 GHSA-f7wc-pcqv-5mwm

Use after free in Mozilla Firefox

LOW 36CWE-416Published 2021-11-03 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 9 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

During process shutdown, a document could have caused a use-after-free of a languages service object, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.

Why it matters now

EPSS 0.01467 73rd percentileScored 2026-11-07

Fix Partial Firefox (Mozilla): 93Thunderbird (Mozilla): 91.2+1 more productRed Hat: 8 advisoriesRed Hat: 9 fixed, 1 without a fix

SSVC decision points

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Mozilla	Firefox	before 93	93	Patch available	CNA
Mozilla	Thunderbird	before 91.2	91.2	Patch available	CNA
Mozilla	Firefox ESR	before 91.2	91.2	Patch available	CNA

Firefox VendorMozilla Affected before 93 Fixed in 93 Patch available CNA
Thunderbird VendorMozilla Affected before 91.2 Fixed in 91.2 Patch available CNA
Firefox ESR VendorMozilla Affected before 91.2 Fixed in 91.2 Patch available CNA

CPE configurations NVD · 3

CPE	Versions	Role	Vendor
cpe:2.3:a:mozilla:firefox::::::::	before 93.0	Vulnerable	Mozilla
cpe:2.3:a:mozilla:firefox_esr::::::::	before 91.2	Vulnerable	Mozilla
cpe:2.3:a:mozilla:thunderbird::::::::	before 91.2	Vulnerable	Mozilla

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 93.0 Vulnerable ·Mozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 91.2 Vulnerable ·Mozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 91.2 Vulnerable ·Mozilla

Remediation

Fix · CNA Firefox (Mozilla) Fixed in 93
Fix · CNA Thunderbird (Mozilla) Fixed in 91.2
Fix · CNA Firefox ESR (Mozilla) Fixed in 91.2

Red Hat 8 advisories

RHSA-2021:3841 Released 2021-10-13 · Red Hat rating Important
thunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-91.2.0-1.el7_9
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-91.2.0-1.el7_9
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-91.2.0-1.el7_9
RHSA-2021:3838 Released 2021-10-13 · Red Hat rating Important
thunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-91.2.0-1.el8_4
RHSA-2021:3839 Released 2021-10-13 · Red Hat rating Important
thunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-91.2.0-1.el8_2

Show 5 more Red Hat advisories

RHSA-2021:3840 Released 2021-10-13 · Red Hat rating Important
thunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-91.2.0-1.el8_1
RHSA-2021:3791 Released 2021-10-12 · Red Hat rating Important
firefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-91.2.0-4.el7_9
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-91.2.0-4.el7_9
- Red Hat Enterprise Linux Server (v. 7) firefox-91.2.0-4.el7_9
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-91.2.0-4.el7_9
- Red Hat Enterprise Linux Workstation (v. 7) firefox-91.2.0-4.el7_9
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-91.2.0-4.el7_9
RHSA-2021:3755 Released 2021-10-11 · Red Hat rating Important
firefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-91.2.0-4.el8_4
RHSA-2021:3757 Released 2021-10-11 · Red Hat rating Important
firefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-91.2.0-4.el8_1
RHSA-2021:3756 Released 2021-10-11 · Red Hat rating Important
firefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox-91.2.0-4.el8_2

Fixed in the same release

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

Release · 2021-11-03
Mozilla Firefox 93
6 records Highest priority Priority MEDIUM 4 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2021-16100 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 41
- TI-2021-16096 Use after free in Mozilla ThunderbirdPriority MEDIUM 41
- TI-2021-16101 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 40
Show all 6 records →
Release · 2021-11-03
Mozilla Thunderbird 91.2
4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2021-16101 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 40
- TI-2021-16097 Origin validation error in Mozilla FirefoxPriority LOW 30
- TI-2021-16102 Thunderbird ignored the configuration to require STARTTLS security for an SMTP connection.Priority LOW 29
Show all 4 records →

Show 1 more group

Release · 2021-11-03
Mozilla Firefox ESR 91.2
3 records Highest priority Priority MEDIUM 1 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2021-16101 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 40
- TI-2021-16097 Origin validation error in Mozilla FirefoxPriority LOW 30
Show all 3 records →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)	Fixed	RHSA-2021:3755, RHSA-2021:3838
Red Hat Enterprise Linux AppStream EUS (v. 8.1)	Fixed	RHSA-2021:3757, RHSA-2021:3840
Red Hat Enterprise Linux AppStream EUS (v. 8.2)	Fixed	RHSA-2021:3756, RHSA-2021:3839
Red Hat Enterprise Linux Client (v. 7)	Fixed	RHSA-2021:3791, RHSA-2021:3841
Red Hat Enterprise Linux Client Optional (v. 7)	Fixed	RHSA-2021:3791
Red Hat Enterprise Linux Server (v. 7)	Fixed	RHSA-2021:3791
Red Hat Enterprise Linux Server Optional (v. 7)	Fixed	RHSA-2021:3791, RHSA-2021:3841
Red Hat Enterprise Linux Workstation (v. 7)	Fixed	RHSA-2021:3791, RHSA-2021:3841
Red Hat Enterprise Linux Workstation Optional (v. 7)	Fixed	RHSA-2021:3791

Timeline

2026-10-02 Threatist record created from CVE-2021-38498
2026-10-03 Alias added: GHSA-f7wc-pcqv-5mwm

References

Advisory 4

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 3444 →

Sources

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