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Fencer Vulns
critical 9.8

CVE-2021-44790 in the critical feed json

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

published 2021-12-20 4 y ago modified 2026-09-08 2 mo ago also BIT-apache-2021-44790 , EUVD-2021-31595

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
96.8%
EPSS 96.8% chance of exploitation in 30 days, percentile 99.8%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • bitnami apache 2.4.52
  • apache http_server 2.4.52
  • tenable tenable.sc 5.20.0
  • apple macos 10.15.7, 11.6.6, 12.4
  • apache2 Debian 14, Debian 13, Debian 12 2.4.52-1

debian advisories DEBIAN-CVE-2021-44790

  • apache2 Ubuntu 18.04 LTS 2.4.29-1ubuntu4.21
  • apache2 Ubuntu 20.04 LTS 2.4.41-4ubuntu3.9
  • apache2 Ubuntu 22.04 LTS 2.4.52-1ubuntu1
  • apache2 Ubuntu Pro 14.04 LTS 2.4.7-1ubuntu4.22+esm3
  • apache2 Ubuntu Pro 16.04 LTS 2.4.18-2ubuntu3.17+esm4

ubuntu advisories UBUNTU-CVE-2021-44790

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd RHEL 7 2.4.6-97.el7_9.4
  • mod_ssl RHEL 7 1:2.4.6-97.el7_9.4
  • mod_ldap RHEL 7 2.4.6-97.el7_9.4
  • httpd-tools RHEL 7 2.4.6-97.el7_9.4
  • mod_session RHEL 7 2.4.6-97.el7_9.4
  • httpd-manual RHEL 7 2.4.6-97.el7_9.4
  • mod_proxy_html RHEL 7 1:2.4.6-97.el7_9.4
  • httpd24-httpd RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.1

red hat advisories RHSA-2022:1137RHSA-2022:1136RHSA-2022:1139RHSA-2022:1138RHSA-2022:0143RHSA-2022:0288

  • apache2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.4.66-150400.6.57.1
  • apache2 SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 2.4.51-35.7.1
  • apache2 SLE Module for Server Applications 15 SP3, SLE Module for Server Applications 15 SP2, SLE Module for Package Hub 15 SP3 +3 more 2.4.51-3.37.1
  • apache2 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 2.4.33-3.61.1
  • apache2 SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES 12 SP4-LTSS +8 more 2.4.23-29.83.1

suse advisories SUSE-SU-2026:2686-1SUSE-SU-2022:0440-1SUSE-SU-2022:0091-2SUSE-SU-2022:0119-1SUSE-SU-2022:0091-1SUSE-SU-2022:0065-1

  • apache2 openSUSE Tumbleweed 2.4.52-1.1
  • apache2 openSUSE Leap 15.3 2.4.51-3.37.1
  • chromium Package Hub 15 SP3, openSUSE Leap 15.3 99.0.4844.84-bp153.2.75.1

opensuse advisories openSUSE-SU-2024:11695-1openSUSE-SU-2022:0091-1

  • httpd AlmaLinux 8 2.4.37-43.module_el8.5.0+2609+b30d9eec.1.alma
  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.5.0+2609+b30d9eec
  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa
  • mod_ssl AlmaLinux 8 1:2.4.37-43.module_el8.5.0+2609+b30d9eec.1.alma
  • mod_ldap AlmaLinux 8 2.4.37-43.module_el8.5.0+2609+b30d9eec.1.alma
  • mod_http2 AlmaLinux 8 1.15.7-3.module_el8.5.0+2609+b30d9eec
  • httpd-tools AlmaLinux 8 2.4.37-43.module_el8.5.0+2609+b30d9eec.1.alma
  • mod_session AlmaLinux 8 2.4.37-43.module_el8.5.0+2609+b30d9eec.1.alma

almalinux advisories ALSA-2022:0258

  • httpd Rocky Linux 8 2.4.37-39.module+el8.4.0+571+fd70afb1
  • httpd Rocky Linux 8 2.4.37-43.module+el8.5.0+714+5ec56ee8
  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.5.0+695+1fa8055e
  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.4.0+553+7a69454b
  • mod_http2 Rocky Linux 8 1.15.7-3.module+el8.4.0+553+7a69454b
  • mod_http2 Rocky Linux 8 1.15.7-3.module+el8.5.0+695+1fa8055e

rocky linux advisories RLSA-2022:0258

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.4.52-r0

alpine advisories ALPINE-CVE-2021-44790

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd CBL-Mariner 2.0 2.4.52-1

azure linux advisories AZL-7044

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-44790 updated cvss 9.8

httpd: mod_lua: Possible buffer overflow when parsing multipart content

  • Red Hat JBoss Enterprise Application Platform 6 httpd, mod_ssl, mod_ldap, httpd-tools, httpd-manual
    affected: workaround, no fix planned “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.”
  • Red Hat Enterprise Linux AppStream (v. 8) mod_md 2.0.8-8.module+el8.3.0+6814+67d1e611, httpd 2.4.37-43.module+el8.5.0+13806+b30d9eec.1, mod_http2 1.15.7-3.module+el8.4.0+8625+d397f3da, mod_ssl 2.4.37-43.module+el8.5.0+13806+b30d9eec.1, mod_ldap 2.4.37-43.module+el8.5.0+13806+b30d9eec.1, httpd-tools 2.4.37-43.module+el8.5.0+13806+b30d9eec.1, +4 more
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0258
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) httpd 2.4.37-16.module+el8.1.0+13809+822d170a.3, mod_md 2.4.37-16.module+el8.1.0+13809+822d170a.3, mod_http2 1.11.3-3.module+el8.1.0+7763+babdfe5b.1, mod_ssl 2.4.37-16.module+el8.1.0+13809+822d170a.3, mod_ldap 2.4.37-16.module+el8.1.0+13809+822d170a.3, httpd-tools 2.4.37-16.module+el8.1.0+13809+822d170a.3, +4 more
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0288
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) mod_md 2.0.8-7.module+el8.2.0+5531+7e4d69a2, httpd 2.4.37-21.module+el8.2.0+13808+dea277df.3, mod_http2 1.11.3-3.module+el8.2.0+7758+84b4ca3e.1, mod_ssl 2.4.37-21.module+el8.2.0+13808+dea277df.3, mod_ldap 2.4.37-21.module+el8.2.0+13808+dea277df.3, httpd-tools 2.4.37-21.module+el8.2.0+13808+dea277df.3, +4 more Red Hat Enterprise Linux AppStream EUS (v.8.4) mod_md 2.0.8-8.module+el8.3.0+6814+67d1e611, httpd 2.4.37-39.module+el8.4.0+13807+c8c001ae.3, mod_http2 1.15.7-3.module+el8.4.0+8625+d397f3da, mod_ssl 2.4.37-39.module+el8.4.0+13807+c8c001ae.3, mod_ldap 2.4.37-39.module+el8.4.0+13807+c8c001ae.3, httpd-tools 2.4.37-39.module+el8.4.0+13807+c8c001ae.3, +4 more
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0258
  • Red Hat Enterprise Linux Client Optional (v. 7) httpd 2.4.6-97.el7_9.4, mod_ssl 2.4.6-97.el7_9.4, mod_ldap 2.4.6-97.el7_9.4, httpd-tools 2.4.6-97.el7_9.4, mod_session 2.4.6-97.el7_9.4, httpd-manual 2.4.6-97.el7_9.4, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) httpd 2.4.6-97.el7_9.4, mod_ssl 2.4.6-97.el7_9.4, mod_ldap 2.4.6-97.el7_9.4, httpd-tools 2.4.6-97.el7_9.4, mod_session 2.4.6-97.el7_9.4, httpd-manual 2.4.6-97.el7_9.4, +1 more Red Hat Enterprise Linux Server (v. 7) httpd 2.4.6-97.el7_9.4, mod_ssl 2.4.6-97.el7_9.4, httpd-tools 2.4.6-97.el7_9.4, mod_session 2.4.6-97.el7_9.4, httpd-manual 2.4.6-97.el7_9.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0143
  • Red Hat Enterprise Linux Server AUS (v. 7.3) httpd 2.4.6-45.el7_3.8, mod_ssl 2.4.6-45.el7_3.8, httpd-tools 2.4.6-45.el7_3.8, httpd-manual 2.4.6-45.el7_3.8
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1139
  • Red Hat Enterprise Linux Server AUS (v. 7.4) httpd 2.4.6-67.el7_4.9, mod_ssl 2.4.6-67.el7_4.9, httpd-tools 2.4.6-67.el7_4.9, mod_session 2.4.6-67.el7_4.9, httpd-manual 2.4.6-67.el7_4.9
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1138
  • Red Hat Enterprise Linux Server AUS (v. 7.6) httpd 2.4.6-89.el7_6.4, mod_ssl 2.4.6-89.el7_6.4, httpd-tools 2.4.6-89.el7_6.4, mod_session 2.4.6-89.el7_6.4, httpd-manual 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
show 17 more
  • Red Hat Enterprise Linux Server AUS (v. 7.7) httpd 2.4.6-90.el7_7.3, mod_ssl 2.4.6-90.el7_7.3, httpd-tools 2.4.6-90.el7_7.3, mod_session 2.4.6-90.el7_7.3, httpd-manual 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Server E4S (v. 7.6) httpd 2.4.6-89.el7_6.4, mod_ssl 2.4.6-89.el7_6.4, httpd-tools 2.4.6-89.el7_6.4, mod_session 2.4.6-89.el7_6.4, httpd-manual 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
  • Red Hat Enterprise Linux Server E4S (v. 7.7) httpd 2.4.6-90.el7_7.3, mod_ssl 2.4.6-90.el7_7.3, httpd-tools 2.4.6-90.el7_7.3, mod_session 2.4.6-90.el7_7.3, httpd-manual 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Server Optional (v. 7) mod_ldap 2.4.6-97.el7_9.4, mod_proxy_html 2.4.6-97.el7_9.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0143
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.3) mod_ldap 2.4.6-45.el7_3.8, mod_session 2.4.6-45.el7_3.8, mod_proxy_html 2.4.6-45.el7_3.8
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1139
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.4) mod_ldap 2.4.6-67.el7_4.9, mod_proxy_html 2.4.6-67.el7_4.9
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1138
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.6) mod_ldap 2.4.6-89.el7_6.4, mod_proxy_html 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.7) mod_ldap 2.4.6-90.el7_7.3, mod_proxy_html 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.6) mod_ldap 2.4.6-89.el7_6.4, mod_proxy_html 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.7) mod_ldap 2.4.6-90.el7_7.3, mod_proxy_html 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.6) mod_ldap 2.4.6-89.el7_6.4, mod_proxy_html 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.7) mod_ldap 2.4.6-90.el7_7.3, mod_proxy_html 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Server TUS (v. 7.6) httpd 2.4.6-89.el7_6.4, mod_ssl 2.4.6-89.el7_6.4, httpd-tools 2.4.6-89.el7_6.4, mod_session 2.4.6-89.el7_6.4, httpd-manual 2.4.6-89.el7_6.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1136
  • Red Hat Enterprise Linux Server TUS (v. 7.7) httpd 2.4.6-90.el7_7.3, mod_ssl 2.4.6-90.el7_7.3, httpd-tools 2.4.6-90.el7_7.3, mod_session 2.4.6-90.el7_7.3, httpd-manual 2.4.6-90.el7_7.3
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:1137
  • Red Hat Enterprise Linux Workstation (v. 7) httpd 2.4.6-97.el7_9.4, mod_ssl 2.4.6-97.el7_9.4, httpd-tools 2.4.6-97.el7_9.4, mod_session 2.4.6-97.el7_9.4, httpd-manual 2.4.6-97.el7_9.4 Red Hat Enterprise Linux Workstation Optional (v. 7) mod_ldap 2.4.6-97.el7_9.4, mod_proxy_html 2.4.6-97.el7_9.4
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0143
  • Red Hat Software Collections for RHEL Workstation(v. 7) httpd24-httpd 2.4.34-23.el7.1, httpd24-mod_ssl 2.4.34-23.el7.1, httpd24-mod_ldap 2.4.34-23.el7.1, httpd24-httpd-tools 2.4.34-23.el7.1, httpd24-mod_session 2.4.34-23.el7.1, httpd24-httpd-manual 2.4.34-23.el7.1, +1 more Red Hat Software Collections for RHEL(v. 7) httpd24-httpd 2.4.34-23.el7.1, httpd24-mod_ssl 2.4.34-23.el7.1, httpd24-mod_ldap 2.4.34-23.el7.1, httpd24-httpd-tools 2.4.34-23.el7.1, httpd24-mod_session 2.4.34-23.el7.1, httpd24-httpd-manual 2.4.34-23.el7.1, +1 more
    fixed: vendor fix “Disabling mod_lua and restarting httpd will mitigate this flaw. See https://access.redhat.com/articles/10649 for more information.” RHSA-2022:0303
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat Enterprise Linux 9 httpd, mod_lua, mod_ssl, mod_ldap, httpd-core, httpd-tools, +4 more Red Hat JBoss Core Services jbcs-httpd24-httpd jbcs-httpd24-httpd
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-22-132-02 updated cvss 9.8

Mitsubishi Electric MELSOFT iQ AppPortal

  • Mitsubishi Electric MELSOFT iQ AppPortal (SW1DND-IQAPL-M) >= 1.00A, <= 1.26C
    affected: mitigation “Update to 1.29F or later. Unzip the downloaded file (zip format) and execute the file “setup.exe.”” mitsubishielectric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Timeline

  1. Published
  2. First public exploit (EDB-51193)

Exploit prediction

96.84% chance of exploitation in the next 30 days, higher than 99.8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-51193 Apache 2.4.x - Buffer Overflow webapps, 2023-04-01
  • packetstormsecurity.com http://packetstormsecurity.com/files/171631/Apache-2.4.x-Buffer-Overflow.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
bitnami apache
<2.4.52
2.4.52

Affected products

  • Apache Software Foundation Apache HTTP Server

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.