Apache Traffic Server up to 8.1.2/9.1.0 HTTP Header Parser request smuggling

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.4$5k-$25k0.00

Summaryinfo

A vulnerability was found in Apache Traffic Server up to 8.1.2/9.1.0. It has been classified as critical. The impacted element is an unknown function of the component HTTP Header Parser. This manipulation causes request smuggling. This vulnerability is registered as CVE-2021-37149. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in Apache Traffic Server up to 8.1.2/9.1.0. Affected by this vulnerability is an unknown code block of the component HTTP Header Parser. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was published 11/03/2021. It is possible to read the advisory at lists.apache.org. This vulnerability is known as CVE-2021-37149 since 07/21/2021. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/28/2025).

The vulnerability scanner Nessus provides a plugin with the ID 258005 (Linux Distros Unpatched Vulnerability : CVE-2021-37149), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (258005). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Request smuggling
CWE: CWE-444
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 258005
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2021-37149

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

07/21/2021 🔍
11/03/2021 +105 days 🔍
11/03/2021 +0 days 🔍
08/28/2025 +1394 days 🔍

Sourcesinfo

Vendor: apache.org

Advisory: lists.apache.org
Status: Confirmed

CVE: CVE-2021-37149 (🔍)
GCVE (CVE): GCVE-0-2021-37149
GCVE (VulDB): GCVE-100-185995

Entryinfo

Created: 11/03/2021 20:33
Updated: 08/28/2025 13:55
Changes: 11/03/2021 20:33 (37), 11/09/2021 08:06 (1), 11/09/2021 08:10 (18), 08/28/2025 13:55 (16)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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