CVE-2025-0243

Code execution via undisclosed memory corruption defects

Published Jan 7, 2025 · Updated Apr 13, 2026

Memory safety defects in Firefox 133, Firefox ESR 128.5, Thunderbird 133, and Thunderbird 128.5 allow attackers to corrupt memory. Mozilla has not published the affected code loci or the operations that mishandle input; its advisory reports only evidence of corruption. Arbitrary code execution remains a vendor-stated presumption; Thunderbird email reading disables scripting, so exposure lies in browser or browser-like contexts.

CVSS severity5.1
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory safety defects in Firefox 133, Firefox ESR 128.5, Thunderbird 133, and Thunderbird 128.5 allow attackers to corrupt memory. Mozilla has not published the affected code loci or the operations that mishandle input; its advisory reports only evidence of corruption. Arbitrary code execution remains a vendor-stated presumption; Thunderbird email reading disables scripting, so exposure lies in browser or browser-like contexts.

The record

CVE
CVE-2025-0243
Published
Jan 7, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 7, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
5.1SUSECVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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