CVE-2021-41767Network attack vector

Active-session access via exposed tunnel identifier

Published Jan 11, 2022 · Updated Aug 4, 2024

Information exposure in Apache Guacamole 1.3.0 and earlier allows remote authenticated users to access another user's active session. Active-connection REST resources place the private GuacamoleTunnel identifier in non-private response details instead of withholding it from peer users. A user with permission to the same connection can use that identifier to read from or interact with the other user's live session.

CVSS severity6.5
Medium
EPSS probability1.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information exposure in Apache Guacamole 1.3.0 and earlier allows remote authenticated users to access another user's active session. Active-connection REST resources place the private GuacamoleTunnel identifier in non-private response details instead of withholding it from peer users. A user with permission to the same connection can use that identifier to read from or interact with the other user's live session.

The record

CVE
CVE-2021-41767
Published
Jan 11, 2022
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Guacamole
Classifications
CWE-200
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 11, 2022CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=1.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Guacamoleversion=unspecified <=1.3.0

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:P/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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