Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-44790

88
FAUCET Score

CVE-2021-44790 is a critical buffer overflow vulnerability affecting Apache HTTP Server versions 2.4.51 and earlier, specifically within the mod_lua multipart parser when processing crafted request bodies. This flaw carries a CVSS score of 9.8 (CRITICAL) due to its network-based attack vector, low attack complexity, and potential for complete compromise of confidentiality, integrity, and availability. While the Apache team is not aware of active exploits, an ExploitDB entry exists, and the vulnerability has garnered significant community discussion and media coverage, indicating high interest and potential for future exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.4.52CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
36CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
97.11%
Probability of exploitation in next 30 days
EPSS Percentile
99.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
ExploitDB: EDB-51193 · Apr 1, 2023
This CVE's current EPSS score of 0.9711 is in the 99th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (20)

apachepatch availablevia llm_extracted
Fixed in: 2.4
microsoftpatch availablevia msrc
Product: cm1 httpd 2.4.52-1 on CBL Mariner 1.0Fixed in: 2.4.52-1
microsoftpatch availablevia msrc
Product: 18935-16820Fixed in: 2.4.52-1
microsoftpatch availablevia msrc
Product: 17030-16823Fixed in: 2.4.52-1
microsoftpatch availablevia msrc
Product: cbl2 httpd 2.4.52-1 on CBL Mariner 2.0Fixed in: 2.4.52-1
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.4 Advanced Update SupportFixed in: httpd-0:2.4.6-67.el7_4.9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.6 Advanced Update Support(Disable again in 2026 - SPRHEL-7118)Fixed in: httpd-0:2.4.6-89.el7_6.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.6 Telco Extended Update SupportFixed in: httpd-0:2.4.6-89.el7_6.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.6 Update Services for SAP SolutionsFixed in: httpd-0:2.4.6-89.el7_6.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Advanced Update SupportFixed in: httpd-0:2.4.6-90.el7_7.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Telco Extended Update SupportFixed in: httpd-0:2.4.6-90.el7_7.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Update Services for SAP SolutionsFixed in: httpd-0:2.4.6-90.el7_7.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: httpd:2.4-8050020220111011611.c5368500
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsFixed in: httpd:2.4-8010020220111012130.c27ad7f8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: httpd:2.4-8020020220111012020.4cda2c84
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: httpd:2.4-8040020220111011738.522a0ee4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: httpd24-httpd-0:2.4.34-23.el7.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.3 Advanced Update SupportFixed in: httpd-0:2.4.6-45.el7_3.8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: httpd-0:2.4.6-97.el7_9.4
View patch

Vendor Advisories (5)

apachellm-apache-f398f8ed28802aa3LOW

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

Mar 2, 2026
apachellm-apache-a7a91ec4c0e9421dHIGH

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

Dec 10, 2025
redhatCVE-2021-44790Important

httpd: mod_lua: Possible buffer overflow when parsing multipart content

Dec 20, 2021
microsoft2021-Dec/CVE-2021-44790Critical

Possible buffer overflow when parsing multipart content in mod_lua of Apache HTTP Server 2.4.51 and earlier

Dec 14, 2021
apachellm-apache-684e4d0003611bd4LOW

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

References

httpd.apache.org / security/vulnerabilities_24.html
Vendor Advisory
packetstormsecurity.com / files/171631/Apache-2.4.x-Buffer-Overflow.html
Exploit
seclists.org / fulldisclosure/2022/May/33
Mailing ListThird Party Advisory
seclists.org / fulldisclosure/2022/May/35
Mailing ListThird Party Advisory
seclists.org / fulldisclosure/2022/May/38
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD
Third Party Advisory
security.gentoo.org / glsa/202208-20
Third Party Advisory
security.netapp.com / advisory/ntap-20211224-0001
Third Party Advisory
support.apple.com / kb/HT213255
Third Party Advisory
support.apple.com / kb/HT213256
Third Party Advisory
support.apple.com / kb/HT213257
Third Party Advisory
debian.org / security/2022/dsa-5035
Third Party Advisory
oracle.com / security-alerts/cpuapr2022.html
PatchThird Party Advisory
oracle.com / security-alerts/cpujan2022.html
PatchThird Party Advisory
tenable.com / security/tns-2022-01
Third Party Advisory
tenable.com / security/tns-2022-03
Third Party Advisory
openwall.com / lists/oss-security/2021/12/20/4
Mailing ListThird Party Advisory