CVE-2021-37148
Request Smuggling - transfer encoding validation
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
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
What each source reports
NVD Score used
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
CVE-2021-37148- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-20
- Updated
- 2026-11-02
CVE ListNo score
Request Smuggling - transfer encoding validation
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
CVE-2021-37148- Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2021-23722No score
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
EUVD-2021-23722- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p9mw-v4q4-qhvj
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an...
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
GHSA-p9mw-v4q4-qhvj- CVSS 3.1
- 7.5 High
CVSS: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
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
CVE-2021-37148- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-37148
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
DEBIAN-CVE-2021-37148- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-37148
Improper input validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests. This issue affects Apache Traffic Server 8.0.0 to 8.1.2 and 9.0.0 to 9.0.1.
- Record
UBUNTU-CVE-2021-37148- CVSS 3.1
- 7.5 High
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
trafficserverDebian:12 | before 9.1.1+ds-1 | 9.1.1+ds-1 |
trafficserverDebian: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 |
trafficserverDebian: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 |
trafficserverUbuntu:16.04:LTS | All versions, plus listed versions 5.3.0-2ubuntu15.3.0-2ubuntu2 | None known |
trafficserverUbuntu: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 |
trafficserverUbuntu: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 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-37148 is a high vulnerability (CVSS 7.5) in Apache Traffic Server, published November 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.70%, the 86th percentile. Fixed in trafficserver 9.1.1+ds-1.