CVE-2021-40856Public exploitNetwork attack vector

Unauthenticated data access via /about/../ path prefix

Published Dec 13, 2021 · Updated Aug 4, 2024

Authentication bypass in Auerswald COMfortel 1400 IP, 2600 IP, and 3600 IP through 2.8F allows remote attackers to read protected data. The web interface treats /about as unauthenticated even when /about/../ prefixes a protected API endpoint, so that endpoint executes without login checks. Access to port 80 is sufficient to retrieve phone and PBX credentials, which permits later authenticated call placement and interception.

CVSS severity7.5
High
EPSS probability50.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Auerswald COMfortel 1400 IP, 2600 IP, and 3600 IP through 2.8F allows remote attackers to read protected data. The web interface treats /about as unauthenticated even when /about/../ prefixes a protected API endpoint, so that endpoint executes without login checks. Access to port 80 is sufficient to retrieve phone and PBX credentials, which permits later authenticated call placement and interception.

The record

CVE
CVE-2021-40856
Published
Dec 13, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-706, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NIST NVDCVSS: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-706Use of Incorrectly-Resolved Name or Reference
T1190Exploit Public-Facing Application

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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