CVE-2021-44790

CRITICALEPSS 100th pctl

9.8

CVSS v3

Description

A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts). The Apache httpd team is not aware of an exploit for the vulnerabilty though it might be possible to craft one. This issue affects Apache HTTP Server 2.4.51 and earlier.

CWE-787Out-of-bounds Write

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.52-1~deb11u2CVE-2021-44790

Fixed in:2.4.52-1CVE-2021-44790

apache2Ubuntu

Fixed in:2.4.7-1ubuntu4.22+esm3USN-5212-2

Fixed in:2.4.18-2ubuntu3.17+esm4USN-5212-2

Fixed in:2.4.29-1ubuntu4.21USN-5212-1

Fixed in:2.4.41-4ubuntu3.9USN-5212-1

apache2-binUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm3USN-5212-2

Fixed in:2.4.18-2ubuntu3.17+esm4USN-5212-2

Fixed in:2.4.29-1ubuntu4.21USN-5212-1

Fixed in:2.4.41-4ubuntu3.9USN-5212-1

httpdWindows application

Affected:2.4.52Fixed in:2.4.52Apache Lounge

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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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

97.11%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

References

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix

Common questions

How do I fix CVE-2021-44790?

Published advisories record a fix for 4 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-2021-44790 being actively exploited?

Not that we know of. CVE-2021-44790 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 97.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.

How severe is CVE-2021-44790?

CVE-2021-44790 has a CVSS v3 base score of 9.8, rated critical. 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-2021-44790 affect?

Published advisories record a fix for apache2 (Debian), apache2 (Ubuntu), apache2-bin (Ubuntu), httpd (Windows application). 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 2025-05-01.