CVE-2026-33930
Received Received - Intake

Stack Buffer Overflow in Apache Traffic Server

Publication date: 2026-07-29

Last updated on: 2026-07-29

Assigner: Apache Software Foundation

Description
Apache Traffic Server copies the client Host header into a fixed-size stack buffer without a bound during redirect handling, so an over-long Host header overflows the stack when redirect following is enabled. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3. Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.

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Meta Information

Published
2026-07-29
Last Modified
2026-07-29
Generated
2026-07-29
AI Q&A
2026-07-29
EPSS Evaluated
N/A
NVD
CVE-2026-33930
EUVD
EUVD-2026-50171

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
apache traffic_server From 8.0.0 (inc) to 8.1.9 (inc)
apache traffic_server From 9.0.0 (inc) to 9.2.14 (inc)
apache traffic_server From 10.0.0 (inc) to 10.1.3 (inc)
apache traffic_server 9.2.15
apache traffic_server 10.1.4

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

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Executive Summary

Apache Traffic Server has a vulnerability where it copies the client's Host header into a fixed-size stack buffer without checking its length during redirect handling. If the Host header is too long, it overflows the stack, potentially causing crashes or allowing code execution.

Detection Guidance

This vulnerability involves a stack buffer overflow due to an over-long Host header during redirect handling in Apache Traffic Server. Detection requires checking for unusual or excessively long Host headers in HTTP requests. Monitor logs for crashes or segmentation faults in Apache Traffic Server processes. Use network traffic analysis tools like tcpdump or Wireshark to inspect HTTP headers for abnormally long Host values.

Impact Analysis

This vulnerability could allow attackers to crash the server or execute arbitrary code by sending a maliciously crafted Host header. It may lead to service disruption or unauthorized access if exploited.

Mitigation Strategies

Upgrade Apache Traffic Server to version 9.2.15 or 10.1.4, which contain fixes for this issue. If upgrading is not immediately possible, disable redirect following in the configuration to prevent the overflow condition. Apply network-level protections to filter or block excessively long Host headers.

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