VulnSocial

CVE-2026-5734Disclosure(mozilla / firefox)

LOWCVSS 9.8 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD 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 was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.

mozilla CVEsBack to dashboard
0.0/ 10 priority

Sources & remediation

Vendor / third-party advisories
Other references
Weakness type (CWE)
CWE-787CWE-120

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • firefox
  • thunderbird

Threat summary

  • 3 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Technical details provided in 1 signal
  • Disclosure: 2 classified signals
  • General: 1 classified signal
  • Peaked 2d ago at 1 mentions (2026-04-07); latest day: 1
  • 3 total mentions across 3 days

Affected systems

Vendors
mozilla
Products
firefoxthunderbird

Deep dive

Activity timeline3 mentions / 3d
00111Mentions · 2026-04-07: 1Mentions · 2026-04-08: 1Mentions · 2026-04-19: 1Technical Details · 2026-04-19: 104-0704-0804-19
Signal classification2 categories
Disclosure
266.7%
General
133.3%
Referenced assets2 URLs
Classification over time
DateTotalLabels
2026-04-071
Disclosure1
2026-04-081
Disclosure1
2026-04-191
General1
Full discourse3 posts
  • CVE@CVEnew
    General

    CVE-2026-5734 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 corrup… https://www.cve.org/CVERecord?id=CVE-2026-5734

    Post summary

    The tweet indicates that CVE-2026-5734 is a memory‑safety issue affecting specified Firefox and Thunderbird releases, but it does not provide any PoC, exploit, or remediation details.

    00000197
    57.2K followersView on X
  • Abdulaziz Alharbi@Alharbi_Abz
    Disclosure

    :اليومي CVE ملخص ال 🔴 CVE-2025-54328 [Samsung Mobile Processor] 🔴 CVE-2026-34208 [SandboxJS library prior to 0.8.36] 🔴 CVE-2026-5734 [Firefox < 149.0.2] 🔴 CVE-2026-0740 [WordPress sites using Ninja Forms - File Uploads plugin version 3.3.26 or lower] #CVE #Cybersecurity

    Post summary

    This post lists several newly disclosed CVEs across multiple products, serving as a brief announcement without further technical or exploit information.

    00000294
    581 followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    Disclosure

    CVE-2026-5734 Memory Safety Bugs in Firefox and Thunderbird ESR Versions https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-5734

    Post summary

    The post merely lists CVE-2026‑5734 as a memory safety issue affecting Firefox and Thunderbird ESR versions, with no additional technical details, PoC, exploit code, patch information, or evidence of active exploitation.

    0000046
    4.0K followersView on X
CPE platform detail4 entries

4 of 4 entries

PartVendorProductVersionTarget SWTarget HW
Appmozillafirefox---
Appmozillafirefox---
Appmozillathunderbird---
Appmozillathunderbird---

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