PatchSiren cyber security CVE debrief
CVE-2018-25368 Nordvpn CVE debrief
CVE-2018-25368 describes a denial-of-service vulnerability in Nord VPN 6.14.31 where unauthenticated attackers can crash the application by submitting an excessively long string in the password field. The vulnerability is triggered when attackers paste a buffer of repeated characters into the password input field during authentication attempts. The CVSS 4.0 vector indicates network attack vector with low attack complexity, no required privileges, and no user interaction, resulting in a HIGH severity score of 8.7. The vulnerability is classified under CWE-789 (Uncontrolled Memory Allocation). The CVE was published on 2026-05-25 and modified on 2026-05-26, with current status marked as Deferred in the NVD. Multiple source references are available including vendor download information and third-party advisory documentation.
- Vendor
- Nordvpn
- Product
- Unknown
- CVSS
- HIGH 8.7
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-25
- Original CVE updated
- 2026-05-26
- Advisory published
- 2026-05-25
- Advisory updated
- 2026-05-26
Who should care
Organizations using Nord VPN 6.14.31 for remote access or VPN services should prioritize patching. Security operations teams should monitor for anomalous authentication patterns. Application security teams should review similar input validation weaknesses in authentication flows. Network administrators managing VPN infrastructure should assess exposure of authentication interfaces.
Technical summary
The vulnerability exists in the password field handling of Nord VPN 6.14.31's authentication mechanism. When processing authentication requests, the application fails to properly validate or limit the length of password input. An attacker can exploit this by sending an excessively long string of repeated characters to the password field, causing uncontrolled memory allocation (CWE-789) that results in application crash. The attack requires no prior authentication and can be executed remotely with low complexity. The CVSS 4.0 scoring reflects network accessibility, low attack complexity, no privilege requirements, and high impact to availability with no confidentiality or integrity impact.
Defensive priority
HIGH
Recommended defensive actions
- Upgrade to a patched version of Nord VPN beyond 6.14.31 if available
- Implement input validation and length restrictions on authentication fields
- Monitor for repeated authentication failures with abnormally large payload sizes
- Consider rate limiting on authentication endpoints to mitigate brute-force and DoS attempts
- Review application crash logs for indicators of exploitation attempts
Evidence notes
Vulnerability affects Nord VPN version 6.14.31 specifically. Attack vector requires no authentication and can be triggered remotely via network access to the authentication interface. The CWE-789 classification suggests memory allocation issues as the underlying weakness. Source references include vendor domain (nordvpn.com) and security advisory from vulncheck.com.
Official resources
2026-05-25T15:16:19.590Z