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Public proof of conceptFix available

CVE-2021-39172

A public proof of concept exists; no exploitation attested.

  • Published2021-08-27
  • Fixed in2.5.1
  • WeaknessCWE-93

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

Cachet is an open source status page system. Prior to version 2.5.1, authenticated users, regardless of their privileges (User or Admin), can exploit a new line injection in the configuration edition feature (e.g. mail settings) and gain arbitrary code execution on the server. This issue was addressed in version 2.5.1 by improving `UpdateConfigCommandHandler` and preventing the use of new lines characters in new configuration values. As a workaround, only allow trusted source IP addresses to access to the administration dashboard.

Timeline

dates in UTC
  1. 2021-08-2723:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 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-2021-39172?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-39172?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Catchethq catchet
BranchAffectedFixed in
2.5< 2.5.12.5.1

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

Fix

  1. Update Catchethq catchet to 2.5.1

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedW1ngLess/CVE-2021-39172-RCE
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.18.8known since 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • CNAweakness (CWE)CWE-93known since 2026-10-23
  • FIRST EPSSEPSS score29.2 %read 2026-11-02
  • PoC-in-GitHubproof of concept1read 2026-11-02
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2021-08-27

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-08-27
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-9jxw-cfrh-jxq6

Frequently asked questions

What is CVE-2021-39172?

Cachet is an open source status page system. Prior to version 2.5.1, authenticated users, regardless of their privileges (User or Admin), can exploit a new line injection in the configuration edition feature (e.g. mail settings) and gain arbitrary code execution on the server. This issue was addressed in version 2.5.1 by improving `UpdateConfigCommandHandler` and preventing the use of new lines characters in new configuration values. As a workaround, only allow trusted source IP addresses to access to the administration dashboard.

Is CVE-2021-39172 actively exploited?

Active exploitation of CVE-2021-39172 has not been confirmed. Its EPSS score was 29.2% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-39172?

CVE-2021-39172 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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