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TI-2021-12741 Aliases CVE-2021-33193GHSA-p9fg-6rr5-38xc

Request splitting via HTTP/2 method injection and mod_proxy

Priority MEDIUM 63Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 6 fixed, 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.

Summary

A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.

Why it matters now

EPSS 0.46179 98th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 4 advisoriesRed Hat: 6 fixed, 2 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache HTTP ServerApache HTTP Server 2.4 2.4.17 to 2.4.48—No fix listedCNA
  • Apache HTTP Server VendorApache Affected Apache HTTP Server 2.4 2.4.17 to 2.4.48 Fixed in — No fix listed CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*2.4.17 to before 2.4.49VulnerableApache
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:a:tenable:tenable.sc:*:*:*:*:*:*:*:*up to 5.19.1VulnerableTenable
cpe:2.3:a:oracle:secure_backup:*:*:*:*:*:*:*:*before 18.1.0.1.0VulnerableOracle
cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*8.8VulnerableOracle
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
  • cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* Versions 2.4.17 to before 2.4.49 Vulnerable ·Apache
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:a:tenable:tenable.sc:*:*:*:*:*:*:*:* Versions up to 5.19.1 Vulnerable ·Tenable
  • cpe:2.3:a:oracle:secure_backup:*:*:*:*:*:*:*:* Versions before 18.1.0.1.0 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:* Versions 8.8 Vulnerable ·Oracle

Remediation

Red Hat 4 advisories

  • RHSA-2022:7143 Released 2022-10-26 · Red Hat rating Moderate
    Red Hat JBoss Core Services Apache HTTP Server 2.4.51 security update
    • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd-2.4.51-28.el7jbcs, jbcs-httpd24-httpd-devel-2.4.51-28.el7jbcs, jbcs-httpd24-httpd-manual-2.4.51-28.el7jbcs +6
    • Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-httpd-2.4.51-28.el8jbcs, jbcs-httpd24-httpd-devel-2.4.51-28.el8jbcs, jbcs-httpd24-httpd-manual-2.4.51-28.el8jbcs +6
  • RHSA-2022:7144 Released 2022-10-26 · Red Hat rating Important
    Red Hat JBoss Core Services Apache HTTP Server 2.4.51 security update
    • Red Hat JBoss Core Services
  • RHSA-2022:6753 Released 2022-09-29 · Red Hat rating Moderate
    httpd24-httpd security and bug fix update
    • Red Hat Software Collections for RHEL Workstation(v. 7) httpd24-httpd-2.4.34-23.el7.5, httpd24-httpd-devel-2.4.34-23.el7.5, httpd24-httpd-manual-2.4.34-23.el7.5 +5
    • Red Hat Software Collections for RHEL(v. 7) httpd24-httpd-2.4.34-23.el7.5, httpd24-httpd-devel-2.4.34-23.el7.5, httpd24-httpd-manual-2.4.34-23.el7.5 +5
Show 1 more Red Hat advisories
  • RHSA-2022:1915 Released 2022-05-10 · Red Hat rating Moderate
    httpd:2.4 security and bug fix update
    • Red Hat Enterprise Linux AppStream (v. 8) httpd-2.4.37-47.module+el8.6.0+14529+083145da.1.aarch64::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+14529+083145da.1.ppc64le::httpd:2.4, httpd-2.4.37-47.module+el8.6.0+14529+083145da.1.s390x::httpd:2.4 +38

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2022:1915
Red Hat JBoss Core ServicesFixed RHSA-2022:7144
Red Hat JBoss Core Services on RHEL 7 ServerFixed RHSA-2022:7143
Red Hat JBoss Core Services on RHEL 8Fixed RHSA-2022:7143
Red Hat Software Collections for RHEL Workstation(v. 7)Fixed RHSA-2022:6753
Red Hat Software Collections for RHEL(v. 7)Fixed RHSA-2022:6753
Not affected: 5 products
  • Red Hat Enterprise Linux 9
  • Red Hat JBoss Core Services on RHEL 7 Server
  • Red Hat JBoss Core Services on RHEL 8
  • Red Hat JBoss Enterprise Application Platform 6
  • Red Hat JBoss Enterprise Web Server 2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33193
  2. 2026-10-03 Alias added: GHSA-p9fg-6rr5-38xc
  3. 2026-10-09 Fix available: RHSA-2022:7144 · Red Hat
  4. 2026-10-09 Fix available: Red Hat JBoss Core Services · Red Hat

References

Exploit 1

Patch 5

Advisory 7

  • TI-2021-18535 Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-18417 Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-25716 Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path. KEVCVSS 3.1CRITICAL 9.1
  • TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
  • TI-2019-00184 Use after free in Apache HTTP Server KEVCVSS 3.1HIGH 7.8
  • TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
See all 349 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences