CVE-2025-2566: Kaleris Navis N4 · Deserialization of Untrusted Data
Affects Kaleris Navis N4Source CVE Database V5
Not known to be exploited · CVSS 9.3 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 24 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Mavencom.kaleris/navis-n4pkg:maven/com.kaleris/navis-n4Other threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Given the absence of official patches, European organizations should immediately implement network-level protections such as strict firewall rules to restrict access to Navis N4 ULC interfaces to trusted IP addresses only. Deploying Web Application Firewalls (WAFs) with custom rules to detect and block suspicious serialized Java objects can help mitigate exploitation attempts. Organizations should conduct thorough network segmentation to isolate Navis N4 servers from general enterprise networks, limiting potential lateral movement. Monitoring and logging of all requests to the Navis N4 ULC should be enhanced to detect anomalous deserialization patterns or unexpected payloads. Additionally, organizations should engage with Kaleris for timely updates and consider temporary disabling or restricting the use of the vulnerable ULC component if operationally feasible. Implementing runtime application self-protection (RASP) or Java security managers to restrict deserialization behavior can provide additional defense layers. Finally, organizations should prepare incident response plans specific to this vulnerability, including rapid containment and forensic analysis capabilities.
Description
Kaleris NAVIS N4 ULC (Ultra Light Client) contains an unsafe Java deserialization vulnerability. An unauthenticated attacker can make specially crafted requests to execute arbitrary code on the server.