CVE-2023-40518

LiteSpeed OpenLiteSpeed before 1.7.18 does not strictly validate HTTP request headers.

Published: 2023-08-14 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-40518 is rated Moderate Risk (42.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.15%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-40518

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.07% 0.15% +0.09%
2 2026-03-01 0.15% 0.07% -0.09%
3 2026-02-04 — 0.15% —

Full EPSS history (39 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-40518

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-40518

Affected software / configurations for CVE-2023-40518

Vendor Product Version Raw CPE
litespeedtech openlitespeed < 1.7.18 cpe:2.3:a:litespeedtech:openlitespeed:*:*:*:*:*:*:*:*

References for CVE-2023-40518

cvelogic Threat Intelligence