CVE-2021-41767 | Private tunnel identifier may be included in the non-private details of active connections

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.

Published: 2022-01-11 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-41767 is rated Moderate Risk (54.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.93%). EPSS rose +1.36% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-41767

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.57% 1.93% +1.36%
2 2026-03-06 0.46% 0.57% +0.12%
3 2025-12-02 — 0.46% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41767

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2021-41767

OS Trackers for CVE-2021-41767

vendor priority summary link
ubuntu medium CVE-2021-41767 medium priority: Ubuntu including 1 source packages (guacamole-server), 14 status rows across 14 suites (bionic, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 7, needs-triage 5, DNE 2. https://ubuntu.com/security/CVE-2021-41767

Affected software / configurations for CVE-2021-41767

Vendor Product Version Raw CPE
apache guacamole <= 1.3.0 cpe:2.3:a:apache:guacamole:*:*:*:*:*:*:*:*

References for CVE-2021-41767

cvelogic Threat Intelligence