Cyber Resilience

CVE-2023-2437

Auth Bypass in Userproplugin Userpro ≤ 5.1.1

Public PoCAuth Bypass
Published
22 November 2023
Modified
08 April 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.068 93th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2023-2437 is a critical-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Userproplugin Userpro. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique External Remote Services (T1133); ranked in the top 7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The UserPro plugin for WordPress, a commercial user-profile and social-login component sold through Codecanyon, contains an authentication-bypass flaw in all versions through 5.1.1. The root cause is insufficient verification of the identity supplied during Facebook-login handling, which maps directly to CWE-287 and CWE-288. The issue carries a CVSS 3.1 score of 9.8.

Unauthenticated attackers who possess a target user’s email address can exploit the flaw to obtain a valid session as that user, including site administrators. The advisory notes that the required email can be obtained by chaining CVE-2023-2448 and CVE-2023-2446, after which the attacker completes the Facebook login flow without further proof of identity. Exploitation requires only network access and no user interaction.

EPSS for the CVE currently stands at 0.7549 with a recorded peak of 0.7679, indicating sustained and moderately high exploitation interest since disclosure. No public evidence of widespread in-the-wild attacks has been reported in the supplied references.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The UserPro plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 5.1.1. This is due to insufficient verification on the user being supplied during a Facebook login through the plugin. This makes it possible for…

more

unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the email. An attacker can leverage CVE-2023-2448 and CVE-2023-2446 to get the user's email address to successfully exploit this vulnerability.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1040 Network Sniffing Credential Access
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network.
T1134 Access Token Manipulation Stealth
Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-2448Same product: Userproplugin Userpro
CVE-2023-6007Same product: Userproplugin Userpro
CVE-2023-2439Same product: Userproplugin Userpro
CVE-2023-2497Same product: Userproplugin Userpro
CVE-2023-6008Same product: Userproplugin Userpro
CVE-2023-2438Same product: Userproplugin Userpro
CVE-2023-2440Same product: Userproplugin Userpro
CVE-2024-0701Same product: Userproplugin Userpro
CVE-2023-2447Same product: Userproplugin Userpro
CVE-2023-6009Same product: Userproplugin Userpro

Affected Assets

userproplugin
userpro
≤ 5.1.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 15 hardening rules · 6 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.4
  • V6.5.4
  • V6.5.5
  • V6.5.7

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-287 CWE-288

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287 CWE-288

Requires adaptive authentication under specific conditions, directly strengthening authentication mechanisms against improper or insufficient authentication.

addresses: CWE-287 CWE-288

Identity providers centralize and enforce authentication mechanisms, reducing improper authentication.

addresses: CWE-287 CWE-288

Mandates unique identification and authentication of non-organizational users, directly mitigating improper authentication.

addresses: CWE-288

Authorizing remote access reduces the ability to bypass authentication via unauthorized alternate remote channels.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Requiring authentication on every channel and path directly eliminates alternate-path bypasses.

PR.AA-04 mostly match
prevents

PR.AA-04 directly enables verification of identity assertions (mostly preventing CWE-287 in that scope) yet leaves many other authentication failure modes unaddressed (only partial prevention overall).

PR.AA-05 mostly match
prevents

Enforcing authorizations and least privilege across all access vectors prevents unauthenticated alternate paths.

PR.IR-01 mostly match
prevents

Protecting networks and environments from unauthorized logical access blocks bypass via undocumented channels.

PR.AA-01 partial match
prevents

PR.AA-01 supplies and governs credentials/tokens that authentication relies on, removing some weak-credential cases, yet leaves verification logic, missing checks, and protocol flaws untouched.

PR.AA-02 partial match
prevents

PR.AA-02 ensures valid enrollment and unique credential binding, which reduces some improper-auth risks at issuance time but leaves runtime claim verification untouched, so each direction only partially addresses the other.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Requiring authentication methods whose strength matches the sensitivity of the data and mandating multi-factor authentication directly blocks attempts to access resources without proving identity.

prevents

Verifying user identity before issuing replacement credentials and forcing changes after compromise reduces the likelihood that authentication bypass can be achieved through stolen or weak credentials.

finds

Security testing can detect alternate-path bypasses but does not prevent them in production.

prevents

Access control policy directly addresses alternate authentication paths by requiring all channels to enforce authentication.

prevents

Mandating segregated approval and oversight for non-human identities reduces the chance that weak or orphaned credentials can be exploited for unauthorized authentication.

prevents

Access rights provisioning and review prevent bypass via unmonitored or alternate channels.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248598 There must be no ".shosts" files on the OL 8 operating system. prevents CWE-288
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-287, CWE-288
Oracle Linux 9 (2 rules)
  • V-271757 OL 9 file systems must not contain shosts.equiv files. prevents CWE-288
  • V-271758 OL 9 file systems must not contain .shosts files. prevents CWE-288
RHEL 7 (4 rules)
  • V-204425 The Red Hat Enterprise Linux operating system must be configured so that the SSH daemon does not allow authentication using an empty password. prevents CWE-287
  • V-204440 Red Hat Enterprise Linux operating systems version 7.2 or newer using Unified Extensible Firmware Interface (UEFI) must require authentication upon booting into single-user and maintenance modes. prevents CWE-288
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-287, CWE-288
RHEL 8 (1 rule)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-287
Ubuntu 22.04 (1 rule)
  • V-260470 Ubuntu 22.04 LTS, when booted, must require authentication upon booting into single-user and maintenance modes. prevents CWE-287
Ubuntu 24.04 (2 rules)
  • V-270675 Ubuntu 24.04 LTS when booted must require authentication upon booting into single-user and maintenance modes. prevents CWE-287
  • V-270714 Ubuntu 24.04 LTS must not allow accounts configured in Pluggable Authentication Modules (PAM) with blank or null passwords. prevents CWE-287

References