CVE-2025-66507 | 1Panel – CAPTCHA Bypass via Client-Controlled Flag

1Panel is an open-source, web-based control panel for Linux server management. Versions 2.0.13 and below allow an unauthenticated attacker to disable CAPTCHA verification by abusing a client-controlled parameter. Because the server previously trusted this value without proper validation, CAPTCHA protections can be bypassed, enabling automated login attempts and significantly increasing the risk of account takeover (ATO). This issue is fixed in version 2.0.14.

Published: 2025-12-09 Last update: 2025-12-10 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-66507 is rated Moderate Risk (41.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). Mandatory action: 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-2025-66507

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 2026-05-19 0.16% 0.14% -0.02%
2 2026-05-08 0.12% 0.16% +0.04%
3 2026-05-06 0.12%

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-66507

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/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:N)
No account or special rights needed—anonymous or random user is enough.
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.
3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-66507

GitHub Security Advisory for CVE-2025-66507

GHSA-qmg5-v42x-qqhq · Severity: high · Ecosystem: go — 1Panel – CAPTCHA Bypass via Client-Controlled Flag

Affected software / configurations for CVE-2025-66507

Vendor Product Version Raw CPE
fit2cloud 1panel < 2.0.14 cpe:2.3:a:fit2cloud:1panel:*:*:*:*:*:*:*:*

References for CVE-2025-66507

cvelogic Threat Intelligence