CVE-2025-1014Network attack vector

Oversized certificate acceptance via mistaken Rust constant

Published Feb 4, 2025 · Updated Apr 13, 2026

Mozilla Firefox before 135, Firefox ESR before 128.7, Thunderbird ESR before 128.7, and Thunderbird before 135 accept oversized certificates. In cert_storage, the length guard casts the u16::max function pointer to an integer instead of comparing against u16::MAX, so overly long certificates pass validation. The affected path processes certificates supplied by Mozilla, and no attacker-controlled input path or practical user impact has been published.

CVSS severity8.8
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Mozilla Firefox before 135, Firefox ESR before 128.7, Thunderbird ESR before 128.7, and Thunderbird before 135 accept oversized certificates. In cert_storage, the length guard casts the u16::max function pointer to an integer instead of comparing against u16::MAX, so overly long certificates pass validation. The affected path processes certificates supplied by Mozilla, and no attacker-controlled input path or practical user impact has been published.

The record

CVE
CVE-2025-1014
Published
Feb 4, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-295
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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