CVE-2023-38522: Apache Traffic Server: Incomplete field name check allows request smuggling

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-26 · updated 2026-06-17
Weakness: CWE-444

Description

Apache Traffic Server accepts characters that are not allowed for HTTP field names and forwards malformed requests to origin servers. This can be utilized for request smuggling and may also lead cache poisoning if the origin servers are vulnerable. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.10, from 9.0.0 through 9.2.4. Users are recommended to upgrade to version 8.1.11 or 9.2.5, which fixes the issue.

Affected products

Apache Software Foundation Apache Traffic Server: from 8.0.0 before 8.1.11; from 9.0.0 before 9.2.5 — fixed in 8.1.11, 9.2.5

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Traffic Server 8.1.11, 9.2.5. Check the vendor advisory for mitigations.

References

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