CVE-2026-3204: Devolutions Server · Improper Input Validation
Affects Devolutions ServerSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 30 Oct 2026, 11:52 UTC
Contested
Critical score, yet low EPSS after six months- EPSS
- 0.6% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 3 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| DevolutionsServer | Affected
| Fixed in– |
AI-suggested
To mitigate CVE-2026-3204, organizations should implement the following specific measures: 1) Monitor and restrict access to Devolutions Server error pages by configuring web server rules or application firewalls to detect and block suspicious URL parameters that could be used for spoofing. 2) Educate users and administrators to be cautious of unexpected error messages and to verify URLs before clicking, especially in emails or messages from untrusted sources. 3) Employ URL filtering and web proxy solutions to detect and block malicious URLs targeting this vulnerability. 4) Regularly audit and monitor server logs for unusual access patterns or error page requests that could indicate exploitation attempts. 5) Engage with Devolutions support channels to obtain updates or patches as soon as they become available and plan for timely application of security updates. 6) Consider implementing additional input validation or sanitization at the network perimeter or via reverse proxies if possible, to reduce the risk of malicious input reaching the server. 7) Use multi-factor authentication and other compensating controls to reduce the impact of potential social engineering attacks that might leverage this vulnerability. These targeted actions go beyond generic advice by focusing on detection, user awareness, and network-level controls.
Description
Improper input validation in the error message page in Devolutions Server 2025.3.16 and earlier allows remote attackers to spoof the displayed error message via a specially crafted URL.