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NVD / CVE Program· CNA Patchstack

CVE-2024-39646: WordPress Custom 404 Pro plugin <= 3.11.1 - Reflected Cross Site Scripting (XSS) vulnerability

Noroxi assessment

Priority: Monitor (action score 24/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB / GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.62% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: Kunal Custom 404 Pro 3.11.2.

Low priority for now. Upgrade to Kunal Custom 404 Pro 3.11.2 or later.

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

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Kunal Custom 404 Pro custom-404-pro.This issue affects Custom 404 Pro: from n/a through <= 3.11.1.

MediumCVSS 6.1 · v3.1—Proof of concept Fix available
Published
Aug 1, 2024
Updated
Jun 17, 2026
EPSS
0.6% · 49th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.1
CNA · Patchstack
7.1
1.0 point gap

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

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

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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
kunalnagarcustom 404 pro

Affected versions

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

  • kunalnagar custom 404 probefore 3.11.2

Versions reported by the vendor

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

  • Kunal Custom 404 Pro

    • up to and including 3.11.1affectedfixed in 3.11.2

Same product

kunalnagar: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-2032Custom 404 Pro < 3.8.1 - Multiple SQL Injection
    39Monitor
  • CVE-2022-47605WordPress Custom 404 Pro Plugin <= 3.7.0 is vulnerable to SQL Injection (SQLi)
    28Monitor
  • CVE-2023-2023Custom 404 Pro < 3.7.3 - Reflected Cross-Site Scripting
    25Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-32740Aug 30, 2023 · WordPress Custom 404 Pro Plugin <= 3.8.1 is vulnerable to Cross Site Scripting (XSS)
    24Monitor
  • ← EarlierCVE-2023-51540Feb 1, 2024 · WordPress Custom 404 Pro Plugin <= 3.10.0 is vulnerable to Cross Site Scripting (XSS)
    24Monitor
  • Later →CVE-2025-9947Oct 11, 2025 · Custom 404 Pro <= 3.12.0 - Authenticated (Administrator+) SQL Injection via `path` Parameter
    19Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Kunal Custom 404 Pro3.11.2Vendor (CNA)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1

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-2024-39646 —

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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

No commit or PR link among the references.

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.

  • CVE-2023-2023429 days apartCustom 404 Pro < 3.7.3 - Reflected Cross-Site Scripting
    25Monitor
  • CVE-2023-51540182 days apartWordPress Custom 404 Pro Plugin <= 3.10.0 is vulnerable to Cross Site Scripting (XSS)
    24Monitor
  • CVE-2023-32740337 days apartWordPress Custom 404 Pro Plugin <= 3.8.1 is vulnerable to Cross Site Scripting (XSS)
    24Monitor

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

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

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

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

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

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

All records