CVE-2021-42091Network attack vector

Server-side requests via malicious integration URL

Published Oct 7, 2021 · Updated Aug 4, 2024

SSRF in Zammad 1.0.x through 4.1.0 allows attackers to make server-side requests through GitHub or GitLab integration URLs. The integration configuration accepts a malicious service URL and causes the application server to request it without adequate destination validation. The flaw is reachable while configuring either integration; public sources do not disclose the required account privilege or which internal resources and data can be reached.

CVSS severity9.1
Critical
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Zammad 1.0.x through 4.1.0 allows attackers to make server-side requests through GitHub or GitLab integration URLs. The integration configuration accepts a malicious service URL and causes the application server to request it without adequate destination validation. The flaw is reachable while configuring either integration; public sources do not disclose the required account privilege or which internal resources and data can be reached.

The record

CVE
CVE-2021-42091
Published
Oct 7, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-918
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 7, 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

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)

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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