CVE-2018-8011

HIGHEPSS 99th pctl

7.5

CVSS v3

Description

By specially crafting HTTP requests, the mod_md challenge handler would dereference a NULL pointer and cause the child process to segfault. This could be used to DoS the server. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.33).

CWE-476NULL Pointer Dereference

How to fix

Remediation Available

httpdAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

httpd-debuginfoAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

httpd-develAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

httpd-filesystemAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

httpd-manualAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

httpd-toolsAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

mod_ldapAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

mod_mdAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

mod_proxy_htmlAmazon

Fixed in:1:2.4.34-1.amzn2.1.0

mod_sessionAmazon

Fixed in:0:2.4.34-1.amzn2.1.0

mod_sslAmazon

Fixed in:1:2.4.34-1.amzn2.1.0

apache2Debian

Fixed in:2.4.34-1CVE-2018-8011

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

56.04%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Vendor Advisory1

httpd.apache.org

Third-Party Advisory2

Other references12

Related Vulnerabilities

Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-21758	High	7.5	93%	-	Fix
CVE-2023-21547	High	7.5	89%	-	Fix
CVE-2014-3470	Medium	4.3	86%	-	Fix
CVE-2021-44224	High	8.2	82%	-	Fix
CVE-2016-0742	High	7.5	82%	-	Fix
CVE-2009-1386	Medium	5.0	80%	-	Fix

Common questions

How do I fix CVE-2018-8011?

Published advisories record a fix for 12 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2018-8011 being actively exploited?

Not that we know of. CVE-2018-8011 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 56.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 99% of all scored CVEs.

How severe is CVE-2018-8011?

CVE-2018-8011 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2018-8011 affect?

Published advisories record a fix for httpd (Amazon), httpd-debuginfo (Amazon), httpd-devel (Amazon), httpd-filesystem (Amazon), and 8 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.