CVE-2025-1014
📋 TL;DR
A certificate validation vulnerability in Mozilla products allows improper certificate length checking when adding certificates to a certificate store. This could potentially enable certificate spoofing or man-in-the-middle attacks. Affects Firefox, Firefox ESR, and Thunderbird users running vulnerable versions.
💻 Affected Systems
- Firefox
- Firefox ESR
- Thunderbird
📦 What is this software?
Firefox by Mozilla
Firefox by Mozilla
Thunderbird by Mozilla
Thunderbird by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Attackers could spoof trusted certificates, enabling man-in-the-middle attacks to intercept and modify encrypted communications, potentially leading to credential theft or data compromise.
Likely Case
Limited impact since only trusted data was processed in practice, but could still enable targeted attacks against specific users or organizations.
If Mitigated
With proper network controls and certificate pinning, impact is minimal as the vulnerability requires specific conditions to be exploitable.
🎯 Exploit Status
Exploitation requires specific conditions and access to manipulate certificate data being added to stores.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 135+, Firefox ESR 128.7+, Thunderbird 128.7+, Thunderbird 135+
Vendor Advisory: https://www.mozilla.org/security/advisories/
Restart Required: Yes
Instructions:
1. Open affected application 2. Go to Help > About 3. Allow automatic update or download latest version from mozilla.org 4. Restart application after update
🔧 Temporary Workarounds
Disable automatic certificate trust
allPrevent automatic addition of certificates to trusted stores
🧯 If You Can't Patch
- Implement network-level certificate pinning
- Use application allowlisting to restrict vulnerable versions
🔍 How to Verify
Check if Vulnerable:
Check application version in Help > About menuCheck Version:
firefox --version or thunderbird --versionVerify Fix Applied:
Verify version is at or above patched versions: Firefox 135+, Firefox ESR 128.7+, Thunderbird 128.7+, Thunderbird 135+📡 Detection & Monitoring
Log Indicators:
- Unusual certificate validation errors
- Multiple certificate store modification attempts
Network Indicators:
- Unexpected certificate changes in TLS handshakes
- Certificate chain validation anomalies
SIEM Query:
source="*firefox*" OR source="*thunderbird*" AND (event="certificate_error" OR event="cert_store_modification")🔗 References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1940804
- https://www.mozilla.org/security/advisories/mfsa2025-07/
- https://www.mozilla.org/security/advisories/mfsa2025-09/
- https://www.mozilla.org/security/advisories/mfsa2025-10/
- https://www.mozilla.org/security/advisories/mfsa2025-11/
- https://lists.debian.org/debian-lts-announce/2025/02/msg00006.html
