CVE-2025-10527Public exploitNetwork attack vectorHinoki check available

Sandbox escape via duplicate DrawTarget reference

Published Sep 16, 2025 · Updated Sep 16, 2025

Canvas2D use-after-free in Firefox before 143, Firefox ESR before 140.3, and Thunderbird before 143 allows attackers to escape a content sandbox. CanvasTranslator's AddDrawTarget accepts a content-supplied reference key twice, frees the replaced DrawTarget, and leaves mCurrentDT pointing to it. Exploitation requires control of a content process and stale-pointer reuse; scripting-disabled email reading does not expose Thunderbird, but browser-like contexts do.

CVSS severity7.1
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Canvas2D use-after-free in Firefox before 143, Firefox ESR before 140.3, and Thunderbird before 143 allows attackers to escape a content sandbox. CanvasTranslator's AddDrawTarget accepts a content-supplied reference key twice, frees the replaced DrawTarget, and leaves mCurrentDT pointing to it. Exploitation requires control of a content process and stale-pointer reuse; scripting-disabled email reading does not expose Thunderbird, but browser-like contexts do.

The record

CVE
CVE-2025-10527
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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 <143

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <143
Mozilla · Thunderbirdversion=unspecified <140.3; version=unspecified <143
Mozilla · Firefox ESRversion=unspecified <140.3

Published CVSS scores

7.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

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-416Use After Free
T1068Exploitation for Privilege Escalation

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