CVE-2021-44790

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-02-08. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
9.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • 808 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 97%
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 97%CVSS: 9.8Exploit: Exploit-DB (verified) · epss top5pct · epss high · public exploitExposed: 808

A fix is available — apply it.

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.

Live · internet exposure

808 internet-exposed hosts are running an affected version of CVE-2021-44790 right now.

across 65 countries (United States, Japan, Germany, France, United Kingdom)top: http_server
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
87(Track*)
EG Risk 87/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation97% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
97%
EPSS %ILE
100%
KEV
Not listed

Published

December 20, 2021

Last Modified

May 1, 2025

Advisory Details (9)

Auto-updated Jun 29, 2026
⚠️ Active exploitation confirmed. Patch available.
generic

[SECURITY] Fedora 34 Update: httpd-2.4.53-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD/
generic

[SECURITY] Fedora 36 Update: httpd-2.4.53-1.fc36 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO/
generic

[SECURITY] Fedora 35 Update: httpd-2.4.53-1.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO/
generic

[SECURITY] Fedora 35 Update: httpd-2.4.52-1.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH/
generic

oss-security - CVE-2021-44790: Apache HTTP Server: Possible buffer overflow when parsing multipart content in mod_lua of Apache HTTP Server 2.4.51 and earlier

http://www.openwall.com/lists/oss-security/2021/12/20/4
generic

Full Disclosure: APPLE-SA-2022-05-16-2 macOS Monterey 12.4

http://seclists.org/fulldisclosure/2022/May/38
generic🔴 Active Exploitation

Full Disclosure: APPLE-SA-2022-05-16-3 macOS Big Sur 11.6.6

http://seclists.org/fulldisclosure/2022/May/35
generic

Full Disclosure: APPLE-SA-2022-05-16-4 Security Update 2022-004 Catalina

http://seclists.org/fulldisclosure/2022/May/33
generic Patch Available🔴 Active Exploitation

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

http://httpd.apache.org/security/vulnerabilities_24.html

Vendor Advisories for CVE-2021-44790(6)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(10)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuapache2-bin (2.4.46-4ubuntu1.5) @ hirsute2026-05-26ubuntu
ubuntuapache2-utils (2.4.18-2ubuntu3.17+esm4) @ xenial2026-05-26ubuntu
redhathttpd-0:2.4.6-45.el7_3.82022-04-01redhat
redhathttpd-0:2.4.6-67.el7_4.92022-04-01redhat
redhathttpd-0:2.4.6-89.el7_6.42022-04-01redhat
redhathttpd-0:2.4.6-90.el7_7.32022-04-01redhat
redhathttpd24-httpd-0:2.4.34-23.el7.12022-01-27redhat
redhathttpd:2.4-8010020220111012130.c27ad7f82022-01-26redhat
redhathttpd:2.4-8040020220111011738.522a0ee42022-01-25redhat
redhathttpd-0:2.4.6-97.el7_9.42022-01-17redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(5)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 3× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 02:05 UTCEG score recompute
  2. 2026-07-22 22:52 UTCEG score recompute
  3. 2026-07-20 17:05 UTCEPSS rescore
  4. 2026-07-18 05:29 UTCOSV refresh
  5. 2026-07-11 08:25 UTCEPSS rescore
  6. 2026-07-11 08:25 UTCEPSS rescore
  7. 2026-06-30 23:20 UTCEPSS rescore
  8. 2026-06-30 23:20 UTCEPSS rescore
  9. 2026-06-30 01:30 UTCOSV refresh
  10. 2026-06-28 04:54 UTCEPSS rescore
  11. 2026-06-28 04:54 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-23 21:31 UTCEPSS rescore
  14. 2026-06-16 17:51 UTCEPSS rescore
  15. 2026-06-16 17:51 UTCEPSS rescore
  16. 2026-06-15 17:46 UTCEPSS rescore
  17. 2026-06-13 22:58 UTCEPSS rescore
  18. 2026-06-13 22:58 UTCEPSS rescore
  19. 2026-06-12 23:10 UTCEPSS rescore
  20. 2026-06-12 14:40 UTCOSV refresh
  21. 2026-06-11 13:58 UTCEPSS rescore
  22. 2026-06-11 13:58 UTCEPSS rescore
  23. 2026-06-10 13:20 UTCEPSS rescore
  24. 2026-06-05 22:45 UTCEPSS rescore
  25. 2026-06-02 20:11 UTCEPSS rescore
Show 17 more
  1. 2026-06-02 20:11 UTCEPSS rescore
  2. 2026-06-01 13:50 UTCEPSS rescore
  3. 2026-06-01 13:50 UTCEPSS rescore
  4. 2026-05-31 00:15 UTCEPSS rescore
  5. 2026-05-31 00:15 UTCEPSS rescore
  6. 2026-05-29 13:42 UTCEPSS rescore
  7. 2026-05-28 13:43 UTCEPSS rescore
  8. 2026-05-28 13:43 UTCEPSS rescore
  9. 2026-05-27 13:39 UTCEPSS rescore
  10. 2026-05-27 13:39 UTCEPSS rescore
  11. 2026-05-26 07:17 UTCEPSS rescore
  12. 2026-05-26 07:17 UTCEPSS rescore
  13. 2026-05-26 07:17 UTCEPSS rescore
  14. 2026-05-26 06:05 UTCEG score recompute
  15. 2026-05-26 06:05 UTCVendor advisory
  16. 2026-05-26 06:05 UTCGHSA enrichment
  17. 2026-05-24 20:12 UTCOSV refresh

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 GitHub PoC) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCnuPacaChi/-CVE-2021-44790
    First seen Dec 5, 2023

    Thực nghiệm CVE-2021-44790

    Open source ↗
  • Exploit-DBEDB-51193✓ verified
    First seen Apr 1, 2023

    Apache 2.4.x - Buffer Overflow

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-44790?
CVE-2021-44790 is a critical vulnerability published on December 20, 2021. 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…
When was CVE-2021-44790 disclosed?
CVE-2021-44790 was first published in the National Vulnerability Database on December 20, 2021, with the most recent update on May 1, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-44790 actively exploited?
CVE-2021-44790 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97% probability of exploitation in the next 30 days, which ranks it in the top 0.1% of all scored CVEs.
What is the CVSS score of CVE-2021-44790?
CVE-2021-44790 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-44790?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-44790, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-44790

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