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Full vulnerability report · 2025
CVE-2025-0240High confidence

Compartment mismatch when parsing JavaScript JSON module

Mozilla · Firefox

4.0MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

2 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivemozjs102Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivemozjs115Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-1572

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

What

Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-416

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedCWE-416
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2025-0026Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Mozilla Firefox, Firefox ESR und Thunderbird ausnutzen, um seine Privilegien zu erhöhen, beliebigen Code auszuführen, vertrauliche Informationen preiszugeben, Sicherheitsmaßnahmen zu umgehen oder Spoofing-Angriffe durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0756Multiples vulnérabilités dans les produits VMware

.cve.org/CVERecord?id=CVE-2024-8096 Référence CVE CVE-2024-8805 https://www.cve.org/CVERecord?id=CVE-2024-8805 Référence CVE CVE-2024-9143 https://www.cve.org/CVERecord?id=CVE-2024-9143 Référence CVE CVE-2024-9287 https://www.cve.org/CVERecord?id=CVE-2024-9287 Référence CVE CVE-2024-9681 https://www.cve.org/CVERecord?id=CVE-2024-9681 Référence CVE CVE-2025-0167 https://www.cve.org/CVERecord?id=CVE-2025-0167 Référence CVE CVE-2025-0237 https://www.cve.org/CVERecord?id=CVE-2025-0237 Référence CVE CVE-2025-0238 https://www.cve.org/CVERecord?id=CVE-2025-0238 Référence CVE CVE-2025-0239 https://www.cve.org/CVERecord?id=CVE-2025-0239 Référence CVE CVE-2025-0240 https://www.cve.org/CVERecord?id=CVE-2025-0240 Référence CVE CVE-2025-0241 https://www.cve.org/CVERecord?id=CVE-2025-0241 Référence CVE CVE-2025-0242 https://www.cve.org/CVERecord?id=CVE-2025-0242 Référence CVE CVE-2025-0243 https://www.cve.org/CVERecord?id=CVE-2025-0243 Référence CVE CVE-2025-0245 https://www.cve.org/CVERecord?id=CVE-2025-0245 Référence CVE CVE-2025-0247 https://www.cve.org/CVERecord?id=CVE-2025-0247 Référence CVE CVE-2025-0395 https://www.cve.org/CVERecord?id=CVE-2025-0395 Référence CVE CVE-2025-0434 https://www.cve.org/CVERecord?id=CVE-2025-0434 Référence CVE CVE-2025-0435 https://www.cve.org/CVERecord?id=CVE-2025-0435 Ré

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0019Multiples vulnérabilités dans Mozilla Thunderbird

De multiples vulnérabilités ont été découvertes dans Mozilla Thunderbird. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, une élévation de privilèges et un déni de service à distance.

Official advisory
CERT-FR · French · CERTFR-2025-AVI-0009Multiples vulnérabilités dans les produits Mozilla

De multiples vulnérabilités ont été découvertes dans les produits Mozilla. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, une élévation de privilèges et un déni de service à distance.

Official advisory
NCSC-NL · Dutch · NCSC-2025-0016Kwetsbaarheden verholpen in Mozilla Firefox en Thunderbird

De kwetsbaarheden omvatten onder andere client-side path traversal, privilege escalation en use-after-free condities. Deze kwetsbaarheden kunnen door kwaadwillenden worden misbruikt om ongeautoriseerde toegang te verkrijgen, crashes te veroorzaken of mogelijkerwijze willekeurige code uit te voeren.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
See the vendor and CVE records for the affected range.
Fixed
128.6 ≤ 128.*; 134 ≤ *
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 7 Jan 2025 · Last source change 13 Apr 2026, 14:30 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-1572
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD modified after enrichment

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-0240 · cve.blacktree.nl