CVE-2021-44040

HTTP request line fuzzing attacks

7.5 HighFix available

Improper Input Validation vulnerability in request line parsing of Apache Traffic Server allows an attacker to send invalid requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.3 and 9.0.0 to 9.1.1.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

1.99%Up 1.1 points since Mar 24, 2022

What each source reports

NVD Score used 7.5

Record: CVE-2021-44040
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness: CWE-20
Updated: 2026-11-02

CVE List No score

HTTP request line fuzzing attacks

Record: CVE-2021-44040
Weakness: CWE-20
Updated: 2026-11-02

EUVDEUVD-2021-30899 No score

Record: EUVD-2021-30899
Updated: 2026-11-03

GitHub AdvisoriesGHSA-6h7p-g96p-26q3 7.5

Improper Input Validation vulnerability in request line parsing of Apache Traffic Server allows...

Record: GHSA-6h7p-g96p-26q3
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-20
Updated: 2026-11-02

OSV 7.5

Record: CVE-2021-44040
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-44040 7.5

Record: DEBIAN-CVE-2021-44040
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVOESA-2022-1692 7.5

trafficserver security update

Apache Traffic Server is an OpenSource HTTP / HTTPS / HTTP/2 / QUIC reverse, forward and transparent proxy and cache.

Security Fix(es):

Record: OESA-2022-1692
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-44040 7.5

Record: UBUNTU-CVE-2021-44040
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`trafficserver` Debian:12	before 9.1.2+ds-1	9.1.2+ds-1
`trafficserver` Debian:10 From an advisory covering 6 CVEs	before 8.0.2+ds-1+deb10u6, plus listed versions 8.0.2+ds-18.0.2+ds-1+deb10u18.0.2+ds-1+deb10u28.0.2+ds-1+deb10u38.0.2+ds-1+deb10u48.0.2+ds-1+deb10u5	8.0.2+ds-1+deb10u6
`trafficserver` Debian:11 From an advisory covering 6 CVEs	before 8.1.1+ds-1.1+deb11u1, plus listed versions 8.1.1+ds-1.1	8.1.1+ds-1.1+deb11u1
`trafficserver` openEuler:20.03-LTS-SP1	before 9.1.2-1.oe1	9.1.2-1.oe1
`trafficserver` openEuler:20.03-LTS-SP3	before 9.1.2-1.oe1	9.1.2-1.oe1
`trafficserver` Ubuntu:18.04:LTS	All versions, plus listed versions 7.0.0-57.1.2+ds-27.1.2+ds-2build17.1.2+ds-3	None known
`trafficserver` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 8.0.5+ds-18.0.5+ds-28.0.5+ds-2build18.0.5+ds-2ubuntu18.0.5+ds-38.0.5+ds-3ubuntu0.1~esm1	None known
`trafficserver` Ubuntu:Pro:22.04:LTS	All versions, plus listed versions 8.1.1+ds-1.19.1.1+ds-2build19.1.1+ds-2ubuntu0.1~esm19.1.1+ds-2ubuntu0.19.1.1+ds-2ubuntu0.1+esm1	None known

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-44040 is a high vulnerability (CVSS 7.5) in Apache Traffic Server, published March 23, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.99%, the 80th percentile. Fixed in trafficserver 9.1.2+ds-1.