CVE-2026-74989Network attack vector

Unspecified impact from undisclosed internal defects

Published Aug 18, 2026 · Updated Aug 20, 2026

Memory-safety defects in Mozilla Firefox 153 and Thunderbird 153 allow remote attackers to trigger unspecified impact in browser contexts. Mozilla groups eleven internal bugs under this CVE but does not disclose the affected components or the incorrect operations they perform. Thunderbird disables scripting while reading mail, so exposure is limited to browser or browser-like contexts; no specific consequence is published.

CVSS severity9.8
Critical
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Memory-safety defects in Mozilla Firefox 153 and Thunderbird 153 allow remote attackers to trigger unspecified impact in browser contexts. Mozilla groups eleven internal bugs under this CVE but does not disclose the affected components or the incorrect operations they perform. Thunderbird disables scripting while reading mail, so exposure is limited to browser or browser-like contexts; no specific consequence is published.

The record

CVE
CVE-2026-74989
Published
Aug 18, 2026
Updated
Aug 20, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo