TI-2026-76877 Aliases CVE-2026-113401 GHSA-rv9p-g4pp-v57h

Denial of service in PDF Viewer of Firefox and Thunderbird

LOW 29CWE-400Published 2026-10-20 · Updated 2026-10-20

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-400.

Summary

Mozilla Firefox and Thunderbird contain a denial-of-service flaw in the PDF Viewer component. The flaw is uncontrolled resource consumption (CWE-400) that can make the application stop responding. A remote, unauthenticated attacker can trigger it if a user interacts with malicious content.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Denial-of-service in the PDF Viewer component. This vulnerability was fixed in Firefox 158.0.1 and Thunderbird 158.0.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00348 28th percentileScored 2026-11-07

Fix Fixed Firefox (Mozilla): 158.0.1Thunderbird (Mozilla): 158.0.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Mozilla	Firefox	—	158.0.1	Patch available	CNA
Mozilla	Thunderbird	—	158.0.1	Patch available	CNA

Firefox VendorMozilla Affected — Fixed in 158.0.1 Patch available CNA
Thunderbird VendorMozilla Affected — Fixed in 158.0.1 Patch available CNA

CPE names Threatist (inferred) · 2

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:mozilla:firefox::::::::	—	—	Mozilla
cpe:2.3:a:mozilla:thunderbird::::::::	—	—	Mozilla

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions — — ·Mozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions — — ·Mozilla

Remediation

Update Firefox and Thunderbird to 158.0.1, which fixes this issue in both products.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Fix · CNA Firefox (Mozilla) Fixed in 158.0.1
Fix · CNA Thunderbird (Mozilla) Fixed in 158.0.1

Timeline

2026-10-20 Threatist record created from CVE-2026-113401
2026-10-20 Alias added: GHSA-rv9p-g4pp-v57h
2026-10-20 Fix available: Mozilla/[email protected] · CNA
2026-10-20 1 new reference · CNA

References

Other 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 4204 →

Sources

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