PatchTheCVECVE-2021-31538: LANCOM R&S Unified Firewall (UF) devices running LCOS FX 10.5 allow Relative Path Traversal.
CVE-2021-31538 is a high-severity flaw (CVSS 7.5) affecting lcos fx. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
LANCOM R&S Unified Firewall (UF) devices running LCOS FX 10.5 allow Relative Path Traversal.
Why this priority
- High severity
- Public exploit reference
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.5% (top 26%) |
| CISA exploited list | No |
| Weakness | CWE-22 |
| Published | 2021-06-10 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-31538?
lcos fx: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2021-31538 being exploited?
CVE-2021-31538 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-31538 affect?
CVE-2021-31538 affects lcos fx. Severity is high (CVSS 7.5). LANCOM R&S Unified Firewall (UF) devices running LCOS FX 10.5 allow Relative Path Traversal.
How urgent is CVE-2021-31538?
Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action