Cyber Resilience

CVE-2025-1014

Crypto Weakness in Mozilla Firefox ≤ 128.7.0

Published
04 February 2025
Modified
13 April 2026
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0038 31th percentile
Risk Priority 64 floored blend · peak EPSS

Summary

CVE-2025-1014 is a high-severity Improper Certificate Validation (CWE-295) vulnerability in Mozilla Firefox. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Adversary-in-the-Middle (T1557); ranked at the 31th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-17 (Public Key Infrastructure Certificates) and SC-23 (Session Authenticity) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-1014 involves improper validation of certificate length when certificates are added to the certificate store in Mozilla products. Although only trusted data was processed in practice, this flaw affects Firefox versions prior to 135, Firefox ESR prior to 128.7, Thunderbird prior to 128.7, and Thunderbird prior to 135. It is classified under CWE-295 (Improper Certificate Validation) with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

A remote attacker can exploit this vulnerability with low attack complexity and no privileges required, though user interaction is necessary. Successful exploitation enables high-impact consequences, including unauthorized access to confidential data, modification of integrity, and disruption of availability.

Mozilla advisories detail the fix applied in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135. Security practitioners should prioritize updating to these patched versions. Additional technical details are available in Mozilla's MFSA2025-07, MFSA2025-09, MFSA2025-10, MFSA2025-11 advisories and Bugzilla bug 1940804.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Certificate length was not properly checked when added to a certificate store. In practice only trusted data was processed. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
T1557.002 ARP Cache Poisoning Credential Access
Adversaries may poison Address Resolution Protocol (ARP) caches to position themselves between the communication of two or more networked devices.
T1557.003 DHCP Spoofing Credential Access
Adversaries may redirect network traffic to adversary-owned systems by spoofing Dynamic Host Configuration Protocol (DHCP) traffic and acting as a malicious DHCP server on the victim network.
T1557.004 Evil Twin Credential Access
Adversaries may host seemingly genuine Wi-Fi access points to deceive users into connecting to malicious networks as a way of supporting follow-on behaviors such as [Network Sniffing](https://attack.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-0239Same product: Mozilla Firefox
CVE-2023-34414Same product: Mozilla Firefox
CVE-2023-0430Same product: Mozilla Thunderbird
CVE-2023-0547Same product: Mozilla Thunderbird
CVE-2025-6433Same product: Mozilla Firefox
CVE-2026-16358Same product: Mozilla Firefox
CVE-2025-14331Same product: Mozilla Firefox
CVE-2024-10460Same product: Mozilla Firefox
CVE-2026-8971Same product: Mozilla Firefox
CVE-2026-2790Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 128.7.0 · ≤ 135.0
mozilla
thunderbird
128.0.1 — 128.7.0 · 131.0 — 135.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 12 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

PKI certificate issuance and acquisition under an approved policy establishes the trusted roots and processes needed for correct validation.

Protecting session authenticity depends on cryptographic mechanisms whose trust depends on correct certificate validation.

Requiring confidentiality and integrity protection of transmitted data drives use of properly validated certificates in protocols such as TLS.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Certificate-based authentication of users/services/hardware directly depends on correct validation.

PR.DS-02 mostly match
prevents

Proper certificate validation is a core mechanism for protecting data-in-transit confidentiality and integrity.

PR.PS-06 mostly match
prevents

Secure development practices explicitly include implementing correct certificate validation logic.

ID.RA-09 partial match
prevents

Assessing authenticity/integrity of acquired software often relies on code-signing certificate validation.

PR.AA-04 partial match
prevents

Identity assertions conveyed via certificates require validation to be verified.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Requiring issuance and validation of public-key certificates under an approved policy reduces the chance that certificates with improper validation will be trusted.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-295
  • V-248531 OL 8, for PKI-based authentication, must validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor. prevents CWE-295
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
RHEL 7 (2 rules)
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
RHEL 8 (2 rules)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295

References