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NVD / CVE Program· CNA Wordfence

CVE-2023-6875: POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress <= 2.8.7 - Authorization Bypass via type connect-app API

Noroxi assessment

Priority: This week (action score 66/100)

  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 90.3% (FIRST EPSS); higher than 99.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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 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.

CriticalCVSS 9.8 · v3.1—Weaponized No fix recorded
Published
Jan 11, 2024
Updated
Jun 17, 2026
EPSS
90.3% · 99th percentile

Report tools

JSON

Action score

66

This week

Don’t wait for the next maintenance window.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
27 / 30 · 90.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
9.8
CNA · Wordfence
9.8
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Is Post SMTP – Complete Email Delivery and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App on your site?

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Is Post SMTP – Complete Email Delivery and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App on your site?

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
wpexpertspost smtp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • wpexperts post smtpup to 2.8.7 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.

  • saadiqbal Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App

    • up to and including 2.8.7affected · semver

Same product

wpexperts: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-52233WordPress POST SMTP Mailer plugin <= 2.8.6 - Broken Access Control on API vulnerability
    39Monitor
  • CVE-2025-22800WordPress Post SMTP plugin <= 2.9.11 - Broken Access Control vulnerability
    35Monitor
  • CVE-2023-3179POST SMTP Mailer < 2.5.7 - Account Takeover via CSRF
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-7027Jan 3, 2024 · POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress <= 2.8.7 - Unauthenticated Stored Cross-Site Scripting via device
    21Monitor
  • ← EarlierCVE-2023-6621Jan 3, 2024 · Post SMTP < 2.8.7 - Reflected Cross-Site Scripting
    24Monitor
  • Later →CVE-2023-6620Jan 15, 2024 · Post SMTP < 2.8.7 - Admin+ SQL Injection
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2023-6875 —
Metasploit moduleauxiliary/admin/http/wp_post_smtp_acct_takeoverWordpress POST SMTP Account Takeoverauxiliary2024-01-10
Proof-of-concept repository on GitHubstars:252024-01-13
Proof-of-concept repository on GitHubstars:62024-01-27
Proof-of-concept repository on GitHubstars:12024-02-05

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-1 d
  2. Published
  3. First PoC+2 d
  4. TodayOct 26, 2026+1019 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-639 · Authorization Bypass Through User-Controlled Key

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.

The bug in code

The whole CWE-639 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const invoice = await Invoice.findById(req.params.id);res.json(invoice);

Fixed

ts
const invoice = await Invoice.findOne({  id: req.params.id,  ownerId: req.user.id,});if (!invoice) return res.sendStatus(404);res.json(invoice);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records