How severe is CVE-2023-40518?

CVE-2023-40518 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2023-40518 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-40518?

CVE-2023-40518 affects Litespeedtech Openlitespeed. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-40518?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-40518 published?

CVE-2023-40518 was published on 2023-08-14 and last updated on 2026-06-17.

CVE-2023-40518

CVE-2023-40518 is a high-severity vulnerability in Litespeedtech Openlitespeed with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Litespeedtech Openlitespeed
Published: 2023-08-14
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2023-40518?: LiteSpeed OpenLiteSpeed before 1.7.18 does not strictly validate HTTP request headers.
How severe is CVE-2023-40518?: CVE-2023-40518 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2023-40518 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-40518?: CVE-2023-40518 affects Litespeedtech Openlitespeed. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-40518?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-40518 published?: CVE-2023-40518 was published on 2023-08-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:litespeedtech:openlitespeed:*:*:*:*:*:*:*:*

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