How severe is CVE-2021-31538?

CVE-2021-31538 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-31538 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31538?

CVE-2021-31538 primarily affects Lancom-systems Lcos Fx. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31538?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-31538 published?

CVE-2021-31538 was published on 2021-06-10 and last updated on 2026-06-17.

CVE-2021-31538

CVE-2021-31538 is a high-severity vulnerability in Lancom-systems Lcos Fx with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Lancom-systems Lcos Fx
Published: 2021-06-10
Last modified: 2026-06-17

Description

LANCOM R&S Unified Firewall (UF) devices running LCOS FX 10.5 allow Relative Path Traversal.

Frequently asked questions

What is CVE-2021-31538?: LANCOM R&S Unified Firewall (UF) devices running LCOS FX 10.5 allow Relative Path Traversal.
How severe is CVE-2021-31538?: CVE-2021-31538 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-31538 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31538?: CVE-2021-31538 primarily affects Lancom-systems Lcos Fx. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31538?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-31538 published?: CVE-2021-31538 was published on 2021-06-10 and last updated on 2026-06-17.

References

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-010.txt

Affected products (4)

cpe:2.3:o:lancom-systems:lcos_fx:10.5:-:*:*:*:*:*:*
cpe:2.3:o:lancom-systems:lcos_fx:10.5:ru1:*:*:*:*:*:*
cpe:2.3:o:lancom-systems:lcos_fx:10.5:ru2:*:*:*:*:*:*
cpe:2.3:o:lancom-systems:lcos_fx:10.5:ru3:*:*:*:*:*:*

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