No exploitation reportedFix available

CVE-2021-41767

Q: Is CVE-2021-41767 actively exploited?

Active exploitation of CVE-2021-41767 has not been confirmed. Its EPSS score was 1.9% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41767?

CVE-2021-41767 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

No exploitation reported by the sources we read.

Published2022-01-11
Fixed in1.3.0
WeaknessCWE-200

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Apache Guacamole 1.3.0 and older may incorrectly include a private tunnel identifier in the non-private details of some REST responses. This may allow an authenticated user who already has permission to access a particular connection to read from or interact with another user's active use of that same connection.

Timeline

dates in UTC

2022-01-1122:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41767?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41767?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD

guacamole

Branch	Affected	Fixed in	Source
1.3	< 1.3.0	1.3.0	OSV

Apache guacamole

Branch	Affected	Fixed in	Source
1.3	≤ 1.3.0	no fix published	NVD

guacamole-server

Branch	Affected	Fixed in	Source
1.3	< 1.3.0	1.3.0	OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update guacamole to 1.3.0

Advisories and patches

lists.apache.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.16.5read 2026-10-23
NVDCVSS 2.04read 2026-10-23
CNAweakness (CWE)CWE-200read 2026-10-23
NVDweakness (CWE)CWE-200read 2026-10-23
FIRST EPSSEPSS score1.9 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Published: 2022-01-11
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-41767?

Is CVE-2021-41767 actively exploited?

Active exploitation of CVE-2021-41767 has not been confirmed. Its EPSS score was 1.9% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41767?

CVE-2021-41767 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

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