CVE-2023-0311Network attack vector

CAPTCHA bypass via unchecked response length

Published Jan 15, 2023 · Updated Apr 7, 2025

Improper authentication in phpMyFAQ before 3.1.10 allows remote attackers to bypass CAPTCHA checks with a crafted response. Captcha::validateCaptchaCode accepts any nonempty response length and queries the shared CAPTCHA table instead of first requiring the configured length. The flaw is reachable only where CAPTCHA protection is enabled, and its consequence is limited to bypassing the CAPTCHA gate on exposed actions.

CVSS severity9.8
Critical
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in phpMyFAQ before 3.1.10 allows remote attackers to bypass CAPTCHA checks with a crafted response. Captcha::validateCaptchaCode accepts any nonempty response length and queries the shared CAPTCHA table instead of first requiring the configured length. The flaw is reachable only where CAPTCHA protection is enabled, and its consequence is limited to bypassing the CAPTCHA gate on exposed actions.

The record

CVE
CVE-2023-0311
Published
Jan 15, 2023
Updated
Apr 7, 2025
Vendor
Thorsten Rinne
Product
phpMyFAQ
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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=unspecified <3.1.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Thorsten Rinne · phpMyFAQversion=unspecified <3.1.10

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.3CVE Program CNA recordCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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-287Improper Authentication
T1190Exploit Public-Facing Application

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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