CVE-2025-3177Public exploitNetwork attack vector

Identity forgery via hard-coded JWT signing key

Published Apr 3, 2025 · Updated Apr 3, 2025

Authentication bypass in the JWT Handler in FastCMS 0.1.5 allows remote authenticated users to forge identity tokens with a known signing key. The handler verifies attacker-supplied HS256 bearer tokens with a fixed default key, so forged userId, username, and auth claims pass signature validation. An attacker must reach an authenticated API and know the published default key; accepted tokens can impersonate an administrator and access protected data.

CVSS severity2.3
Low
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in the JWT Handler in FastCMS 0.1.5 allows remote authenticated users to forge identity tokens with a known signing key. The handler verifies attacker-supplied HS256 bearer tokens with a fixed default key, so forged userId, username, and auth claims pass signature validation. An attacker must reach an authenticated API and know the published default key; accepted tokens can impersonate an administrator and access protected data.

The record

CVE
CVE-2025-3177
Published
Apr 3, 2025
Updated
Apr 3, 2025
Vendor
Guangzhou Xiaojudeng Information Technology Co., Ltd.
Product
FastCMS
Classifications
CWE-321, CWE-320, T1606
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2025Record 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=0.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Guangzhou Xiaojudeng Information Technology Co., Ltd. · FastCMSversion=0.1.5

Published CVSS scores

5.0VulDBCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
5.0VulDBCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
4.6VulDBAV:N/AC:H/Au:S/C:P/I:P/A:P
2.3VulDBCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
8.1NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-321Use of Hard-coded Cryptographic Key
CWE-320Key Management Errors
T1606Forge Web Credentials

Public exploit references

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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