Cyber Resilience

CVE-2023-6875

Access Control in Wpexperts Post Smtp ≤ 2.8.7

Public PoCHigh EPSSAccess Control
Published
11 January 2024
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 0.90 99.8th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2023-6875 is a critical-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Wpexperts Post Smtp. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 0.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

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 POST SMTP Mailer plugin for WordPress, in all versions through 2.8.7, contains a type-juggling flaw in the connect-app REST endpoint that permits unauthorized data access and modification. The affected component is the mobile REST API handler responsible for API-key authentication and log retrieval.

Unauthenticated attackers can invoke the endpoint to reset the mailer API key and read stored logs that contain password-reset emails, directly enabling full site takeover. The issue is tracked under CWE-639 and CWE-862 and carries a CVSS 3.1 score of 9.8.

Public references point to a patched changeset in the plugin repository and a detailed advisory from Wordfence that describe the authorization bypass; administrators are expected to apply the vendor update that closes the endpoint flaw. CVE-2023-52233 is noted as a duplicate. The associated EPSS score remains elevated near 0.94, and public exploit code has been posted to Packet Storm.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress plugin for WordPress is vulnerable to unauthorized access of data and modification of data due to a type juggling issue on the connect-app REST…

more

endpoint in all versions up to, and including, 2.8.7. This makes it possible for unauthenticated attackers to reset the API key used to authenticate to the mailer and view logs, including password reset emails, allowing site takeover. CVE-2023-52233 appears to be a duplicate of this issue.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
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.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1556 Modify Authentication Process Defense Impairment
Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-52233Same product: Wpexperts Post Smtp
CVE-2025-22800Same product: Wpexperts Post Smtp
CVE-2024-43214Same vendor: Wpexperts
CVE-2024-31297Same vendor: Wpexperts
CVE-2024-1639Same vendor: Wpexperts
CVE-2024-2538Shared CWE-639, CWE-862
CVE-2025-1667Shared CWE-639, CWE-862
CVE-2024-13719Shared CWE-639, CWE-862
CVE-2024-4341Shared CWE-639, CWE-862
CVE-2024-1744Shared CWE-639, CWE-862

Affected Assets

wpexperts
post smtp
≤ 2.8.7

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

Enforcing approved authorizations on every access request structurally stops a user-controlled key from reaching another user's data.

Requiring explicit access-control decisions on each request blocks unauthorized key-driven access.

AC-25 requires a tamperproof, always-invoked reference monitor that ensures authorization checks cannot be omitted.

Least-privilege restrictions limit the scope of data reachable even if a key check is bypassed.

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-05 full match
prevents

Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.

PR.IR-01 mostly match
prevents

Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.

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.

finds

Security testing can detect missing authorization checks but does not prevent the weakness in production.

prevents

Information access restriction explicitly enforces that users may only retrieve data they are authorized to see, directly addressing user-controlled key bypass.

prevents

Access control policy directly requires enforcement of authorization rules that prevent unauthorized access via manipulated keys.

prevents

Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.

mitigates

Segregating the approval of access rights from their implementation provides an independent check that reduces the impact of missing authorization checks in the resulting system configuration.

finds

By requiring competent outsiders to verify that every function enforces the need-to-know principle, the control lowers the likelihood that missing authorization checks persist undetected.

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-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-862
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-862
RHEL 7 (2 rules)
  • V-251704 The Red Hat Enterprise Linux operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-862
  • V-204429 The Red Hat Enterprise Linux operating system must be configured so that users must provide a password for privilege escalation. prevents CWE-862

References