High severity · published Nov 3, 2021
CVE-2021-37149
Improper Input Validation vulnerability in header parsing of Apache Traffic Server allows an attacker to smuggle requests
7.5
CVSS
2.7%
EPSS
No
On KEV
Description
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 9.1.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)2.7% · higher than 86% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DL
Debian Linux · Debian
10.0; 11.0 · source: NVD
TS
Traffic Server · Apache
8.0.0 through 8.1.2; 9.0.0 through 9.1.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-37149
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-37149
Mailing List
https://lists.apache.org/thread/k01797hyncx53659wr3o72s5cvkc3164
Third Party Advisory
https://www.debian.org/security/2022/dsa-5153
More from Traffic Server
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10.0
CVE-2026-58150
Apache Traffic Server: HTTP/2 requests with Transfer-Encoding are not rejected, allowing request smuggling
10.0
CVE-2026-57834
Apache Traffic Server: Malformed chunked message body allows request smuggling
9.8
CVE-2026-58185
Apache Traffic Server: Use-after-free in the intercept plugin
9.8
CVE-2026-58179
Apache Traffic Server: regex_remap plugin overflows the stack from attacker input