CVE-2021-36091Network attack vector

Appointment disclosure via missing calendar authorization

Published Jul 26, 2021 · Updated Sep 16, 2024

Incorrect authorization in OTRS calendar views allows remote authenticated users to list appointments from inaccessible calendars. OTRS AG has not published the affected request handler or the missing authorization operation that permits cross-calendar listing. An authenticated agent account is required, and the disclosed consequence is limited to reading otherwise inaccessible appointment information.

CVSS severity3.5
Low
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in OTRS calendar views allows remote authenticated users to list appointments from inaccessible calendars. OTRS AG has not published the affected request handler or the missing authorization operation that permits cross-calendar listing. An authenticated agent account is required, and the disclosed consequence is limited to reading otherwise inaccessible appointment information.

The record

CVE
CVE-2021-36091
Published
Jul 26, 2021
Updated
Sep 16, 2024
Vendor
OTRS AG
Product
OTRS
Classifications
CWE-863, CWE-200, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=7.0.x <7.0.27

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OTRS AG · OTRSversion=7.0.x <7.0.27
OTRS AG · ((OTRS)) Community Editionversion=6.0.1 <6.0.x*

Published CVSS scores

4.0NISTAV:N/AC:L/Au:S/C:P/I:N/A:N
3.5OTRS AGCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
4.3NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

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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