CVE-2026-13697

HIGH
Published Jul 29, 2026 Modified Jul 29, 2026 CWE-200 CWE-248 CWE-525

Description

undici's cache interceptor mishandles malformed Cache-Control private directives. In undici 7.0.0 up to before 7.29.0 and 8.0.0 up to before 8.9.0, a response carrying a degenerate qualified private directive, such as private set to an empty value, can be stored in the default shared cache and later served to a different caller with the same cache key, disclosing private response bodies and headers including Set-Cookie. Separately, a Cache-Control header that combines an unqualified private directive with a qualified one triggers an uncaught TypeError in the cache-control parser, which rejects the request and, depending on the consumer's error handling, can terminate the process. Both issues affect applications using the cache interceptor in shared mode, including the default configuration. The issues are fixed in undici 7.29.0 and 8.9.0.

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CVSS v3.1 Score

7.4
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H

Weakness Type (CWE)

CWE-200 CWE-200
CWE-248 CWE-248
CWE-525 CWE-525

References

Frequently Asked Questions

What is CVE-2026-13697? +
undici's cache interceptor mishandles malformed Cache-Control private directives. In undici 7.0.0 up to before 7.29.0 and 8.0.0 up to before 8.9.0, a response carrying a degenerate qualified private directive, such as private set to an empty value, can be stored in the default shared cache and later served to a different caller with the same cache key, disclosing private response bodies and headers including Set-Cookie. Separately, a Cache-Control header that combines an unqualified private directive with a qualified one triggers an uncaught TypeError in the cache-control parser, which rejects the request and, depending on the consumer's error handling, can terminate the process. Both issues affect applications using the cache interceptor in shared mode, including the default configuration. The issues are fixed in undici 7.29.0 and 8.9.0. It has a CVSS v3.1 base score of 7.4 (HIGH).
How severe is CVE-2026-13697? +
CVE-2026-13697 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
How do I check if I'm vulnerable to CVE-2026-13697? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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