CVE-2025-11711Public exploitNetwork attack vector

Protected property modification via unwritable iterator indices

Published Oct 14, 2025 · Updated Oct 14, 2025

Type confusion in Firefox, Firefox ESR, and Thunderbird allows remote attackers to modify protected JavaScript object properties. SpiderMonkey's PropertyEnumerator recorded data-property slots without checking whether their descriptors were writable, allowing optimized enumeration to use invalid assignment targets. Affected releases are Firefox before 144, Firefox ESR before 115.29 and before 140.4, Thunderbird before 140.4 and before 144; exploitation requires user interaction, and the public proof of concept reaches a JSON.stringify crash.

CVSS severity6.5
Medium
EPSS probability0.23%
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

Type confusion in Firefox, Firefox ESR, and Thunderbird allows remote attackers to modify protected JavaScript object properties. SpiderMonkey's PropertyEnumerator recorded data-property slots without checking whether their descriptors were writable, allowing optimized enumeration to use invalid assignment targets. Affected releases are Firefox before 144, Firefox ESR before 115.29 and before 140.4, Thunderbird before 140.4 and before 144; exploitation requires user interaction, and the public proof of concept reaches a JSON.stringify crash.

The record

CVE
CVE-2025-11711
Published
Oct 14, 2025
Updated
Oct 14, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-591, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2025Record 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <144

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <144
Mozilla · Thunderbirdversion=unspecified <140.4; version=unspecified <144
Mozilla · Firefox ESRversion=unspecified <115.29; version=unspecified <140.4

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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 exploitPublished

Weakness, pattern, technique

CWE-591Sensitive Data Storage in Improperly Locked Memory
T1203Exploitation for Client Execution

Public exploit references

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