CVE-2026-109338
Deferred Deferred - Pending Action

SurrealDB Denial of Service via Non-ASCII Headers

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
SurrealDB before 3.3.0 contains a denial of service vulnerability that allows query-capable users to crash the server by reading non-ASCII header values in embedded JavaScript. Attackers with scripting enabled can read such values via Headers get(), entries(), values(), or getSetCookie(), or return them from fetch() endpoints, aborting the server process.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109338
EUVD
EUVD-2026-97640

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
surrealdb surrealdb 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-248 An exception is thrown from a function, but it is not caught.

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Executive Summary

SurrealDB before version 3.3.0 has a denial of service vulnerability where authenticated users with scripting access can crash the server by reading non-ASCII header values in embedded JavaScript. This happens when methods like Headers.get() or fetch() process malformed headers, causing an uncaught exception that terminates the server process.

Detection Guidance

To detect this vulnerability, check if your SurrealDB version is below 3.3.0. Use the command: surrealdb version. If the version is older, the system is vulnerable. Additionally, monitor server crashes when non-ASCII headers are processed in JavaScript functions like Headers.get() or fetch().

Test by sending a request with non-ASCII header values to a fetch() endpoint or Headers object. If the server crashes, the vulnerability is present.

Impact Analysis

This vulnerability allows attackers with query permissions to crash the SurrealDB server, disrupting service for all users and databases until the server is manually restarted. The impact is limited to servers with embedded scripting enabled, which is off by default.

Mitigation Strategies

Upgrade SurrealDB to version 3.3.0 or later immediately. If upgrading is not possible, disable embedded scripting in the configuration. Restrict user access to scripting features and limit endpoints using fetch().

Use an orchestrator to automatically restart the server if it crashes. Ensure guest users cannot access scripting if enabled. Monitor server logs for crashes caused by non-ASCII headers.

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