Vulnary
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Critical· 9.8official fix available

CVE-2026-16361

CVE-2026-16361 is a critical memory safety vulnerability (CWE-119) in Thunderbird ESR 140.12 that could allow attackers to execute arbitrary code via memory corruption. A fix exists in Thunderbird 140.13 and Firefox ESR 140.13.

publishedJul 21, 2026
last modifiedJul 24, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
23th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 20, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Users of Thunderbird ESR 140.12

02

Real-world impact

Potential remote code execution without user interaction or privileges

03

Why this severity

CVSS 9.8 (critical) due to high confidence in exploitability and complete system compromise risk

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade Thunderbird to version 140.13 or later
  2. 02Upgrade Firefox ESR to version 140.13 or later if using Firefox-based Thunderbird

NVD description stating fix availability in Thunderbird 140.13 and Firefox ESR 140.13

05

Timeline

  1. Jul 21, 2026 · 12d ago
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 21, 2026 · 11d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Jul 24, 2026 · 9d ago
    Advisory updated
    The NVD record was last revised.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →