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Traffic ServerApplication · Apache

CVE-2023-38522

HIGH · 7.5 CVSS v3.1 Published 2024-07-26
Fix available
A fix is available. Upgrade to 8.1.11 / 9.2.5 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache Traffic Server fails to properly validate HTTP field names, accepting characters that violate HTTP specifications. When forwarding these malformed requests to origin servers, it can cause request smuggling due to desynchronization between the proxy and origin server parsing, potentially leading to cache poisoning.

MitigationUpgrade Apache Traffic Server to version 8.1.11 or 9.2.5 which contains proper validation of HTTP field names.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Traffic ServerApplication
Affected:>= 8.0.0, < 8.1.11>= 9.0.0, < 9.2.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Apache Traffic Server version
    Run 'traffic_ctl version' or check the installed package (e.g., 'rpm -q traffic-server', 'dpkg -l apache-traffic-server')
    Affected if The version returned is >= 8.0.0 and < 8.1.11, OR >= 9.0.0 and < 9.2.5
  2. Confirm Traffic Server is configured as a forward proxy
    Check the configuration file (records.config or traffic_server.yaml) for 'proxy.config.url_remap.pristine_host_hdr' set to 1, or verify that ATS is accepting origin server definitions in remap.config for forward proxy operation
    Affected if ATS is configured to forward HTTP requests to origin servers (proxy mode)
  3. Verify the proxy service is running and accepting connections
    Run 'traffic_ctl server start' to check status, or use 'netstat'/'ss' to confirm the ATS proxy port (default 8080) is listening
    Affected if ATS is actively running as a proxy server processing forwarded requests

You are affected if Apache Traffic Server is running with a version in the vulnerable range AND is configured to forward HTTP requests to origin servers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.1.11 / 9.2.5 or later
Fixed in 8.1.119.2.5
Interim mitigation

Upgrade Apache Traffic Server to version 8.1.11 or 9.2.5 which contains proper validation of HTTP field names.

Recommended fix High confidence

Upgrade to 8.1.11 (if on 8.x) or 9.2.5 (if on 9.x)

  1. 1. Identify the currently installed Apache Traffic Server version using: traffic_server -V or ats -V
  2. 2. Backup the current Traffic Server configuration directory (typically /etc/trafficserver or /usr/local/etc/trafficserver)
  3. 3. Stop the Apache Traffic Server service: systemctl stop trafficserver or service trafficserver stop
  4. 4. Download the appropriate fixed release from Apache Traffic Server mirrors: For 8.x branch use 8.1.11, for 9.x branch use 9.2.5
  5. 5. Install the new package using your system's package manager (apt, yum, dnf) or compile from source if using custom builds
  6. 6. Verify the installation was successful by checking the version: traffic_server -V
  7. 7. Review and restore any custom configurations from the backup if needed
  8. 8. Start the Apache Traffic Server service: systemctl start trafficserver or service trafficserver start
Caveat Review Apache Traffic Server release notes for any configuration or behavior changes between your current version and the target fixed release

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Traffic Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-38522 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data