CVE-2023-25735Network attack vector

Use-after-free via scripted proxy compartment mismatch

Published Jun 2, 2023 · Updated Jan 9, 2025

Use-after-free in SpiderMonkey in Firefox before 110 and Firefox ESR and Thunderbird before 102.8 lets remote attackers trigger stale-object access. A cross-compartment wrapper stores a scripted proxy's foreign-compartment objects in the main compartment, then unwraps the proxy after their lifetime ends. Exploitation requires script execution in a browser-like context; ordinary Thunderbird mail reading disables scripting and does not expose this path.

CVSS severity8.8
High
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in SpiderMonkey in Firefox before 110 and Firefox ESR and Thunderbird before 102.8 lets remote attackers trigger stale-object access. A cross-compartment wrapper stores a scripted proxy's foreign-compartment objects in the main compartment, then unwraps the proxy after their lifetime ends. Exploitation requires script execution in a browser-like context; ordinary Thunderbird mail reading disables scripting and does not expose this path.

The record

CVE
CVE-2023-25735
Published
Jun 2, 2023
Updated
Jan 9, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <110

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <110
Mozilla · Thunderbirdversion=unspecified <102.8
Mozilla · Firefox ESRversion=unspecified <102.8

Published CVSS scores

8.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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

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Your stack

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