CVE-2021-31538Public exploitNetwork attack vector

Unauthenticated sensitive-file read via path traversal

Published Jun 10, 2021 · Updated Aug 3, 2024

Relative path traversal in LANCOM R&S Unified Firewall LCOS FX 10.5 allows remote attackers to read sensitive files via crafted web requests. The web service fails to sanitize user-supplied path components, letting requests escape the intended directory and access files such as /etc/passwd and /etc/shadow with high service privileges. No authentication is required, and the demonstrated impact is unauthorized confidentiality loss through file disclosure.

CVSS severity7.5
High
EPSS probability1.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Relative path traversal in LANCOM R&S Unified Firewall LCOS FX 10.5 allows remote attackers to read sensitive files via crafted web requests. The web service fails to sanitize user-supplied path components, letting requests escape the intended directory and access files such as /etc/passwd and /etc/shadow with high service privileges. No authentication is required, and the demonstrated impact is unauthorized confidentiality loss through file disclosure.

The record

CVE
CVE-2021-31538
Published
Jun 10, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-23, CWE-22, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-23Relative Path Traversal
CWE-22Path Traversal: '.../.../.../.../.../.../.../.../.../.../.../'
T1005Data from Local System

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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