Which products and versions are affected by CVE-2023-40000?

Affected: Litespeed Cache (Litespeedtech) versions >= n/a. The full list is in the CVE brief.

Is CVE-2023-40000 being exploited in the wild?

It is exploited in the wild, listed in Industry KEV feed since May 3, 2024.

Is CVE-2023-40000 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2023-40000?

Public exploit code is available.

Is there a fix for CVE-2023-40000?

Fixed versions are available, including Litespeed Cache 5.7.0.1.

How urgently should CVE-2023-40000 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2023-40000

MediumExploitedPublic exploit

LiteSpeed Cache <= 5.7 - Unauthenticated Stored Cross-Site Scripting via 'nameservers' and '_msg'

Published Feb 26, 2024 · Updated Apr 28, 2026 · Also known as d4c27c06-214a-4c20-80d0-b6b4d18737c3

Key Facts

Patch immediately

CVE-2023-40000 is a medium-severity vulnerability (CVSS 6.1 v3.1) affecting Litespeed Cache (Litespeedtech).
It is exploited in the wild, listed in Industry KEV feed since May 3, 2024. Public exploit code is available.
EPSS estimates a 55% probability of exploitation in the next 30 days.
Fixed versions are available, including Litespeed Cache 5.7.0.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

6.1

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

EPSS (30-day exploit likelihood)

55%

Higher than 99.0% of all scored CVEs

Exploited in the wild

Yes

1 catalog listing

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2023-40000 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache allows Stored XSS.This issue affects LiteSpeed Cache: from n/a through 5.7.

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
Industry KEV feed	May 3, 2024	n/a	Not reported

Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Affected Products

3 affected entries in total

Product	Affected versions	Fixed in
Litespeed CacheLitespeedtech	>= n/a	5.7.0.1

Patched Releases

Litespeed Cache

5.7.0.1

Timeline

Publicly disclosed
Feb 26, 2024
Added to Industry KEV feed
May 3, 2024
Last updated
Apr 28, 2026

Weakness Type

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

References

2 more references in the full CVE brief

FAQ

Common Questions.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache allows Stored XSS.This issue affects LiteSpeed Cache: from n/a through 5.7.
Affected: Litespeed Cache (Litespeedtech) versions >= n/a. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since May 3, 2024.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Litespeed Cache 5.7.0.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2023-40000 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.