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2914 articles · 109744 vulns · 38/41 feeds (7d)
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9.8
CVE-2026-5734EXPLOITEDPATCHED
mozilla · firefox

Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2

Description

Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149.0.2, Firefox ESR < 140.9.1, Thunderbird < 149.0.2, and Thunderbird < 140.9.1.

Affected Products

VendorProductVersions
mozillafirefoxunspecified, unspecified, unspecified, unspecified

Also Affects

Downstream vendors/products affected by this vulnerability

VendorProductSourceConfidence
mozillathunderbirdcve_cpe95%

References

  • https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022369%2C2023026%2C2023545%2C2023555%2C2023958%2C2025422%2C2025468%2C2025492%2C2025505
  • https://www.mozilla.org/security/advisories/mfsa2026-25/
  • https://www.mozilla.org/security/advisories/mfsa2026-27/
  • https://www.mozilla.org/security/advisories/mfsa2026-28/
  • https://www.mozilla.org/security/advisories/mfsa2026-29/

Related News (2 articles)

Tier B
CERT-FR2d ago
Multiples vulnérabilités dans les produits Mozilla (08 avril 2026)
→ No new info (linked only)
Tier C
VulDB2d ago
CVE-2026-5734 | Mozilla Firefox up to 149.0.1 memory corruption
→ No new info (linked only)
CVSS 3.19.8 NONE
CISA KEV❌ No
Actively exploited✅ Yes
Patch available
149.0.2140.9.1
PublishedApr 7, 2026
Last enriched2d agov2
Tags
memory corruptionCVE-2026-5734
Trending Score37
Source articles2
Independent2
Info Completeness8/14
Missing: cvss, epss, kev, exploit, iocs, mitre_attack

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Related CVEs (5)

HIGHCVE-2026-5732EXP
Incorrect boundary conditions, integer overflow in the Graphics: Text component
Trending: 42
NONECVE-2026-5735EXP
Memory safety bugs fixed in Firefox 149.0.2 and Thunderbird 149.0.2
Trending: 40
CRITICALCVE-2026-5731
Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2
Trending: 33
HIGHCVE-2026-5733
Incorrect boundary conditions in the Graphics: WebGPU component
Trending: 31
HIGHPRE-CVE
Multiple Vulnerabilities in Mozilla Firefox and Thunderbird Allow Denial of Service and Arbitrary Code Execution
Trending: 19

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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
Apr 7, 2026
Discovered by ZDM
Apr 7, 2026
Updated: severity, activelyExploited, cweIds, tags
Apr 7, 2026
Actively Exploited
Apr 8, 2026
Patch Available
Apr 8, 2026

Version History

v2
Last enriched 2d ago
v2Tier C2d ago

Updated severity to CRITICAL, marked as actively exploited, and added CWE-119 and new tags.

severityactivelyExploitedcweIdstags
via VulDB
v12d ago

Initial creation