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.
Published: 2026-07-29
Score: 7.4 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-4cwx-7wf7-3272 undici vulnerable to cross-user information disclosure and parse-time crash via degenerate private cache directives
History

Wed, 05 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-524
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Important


Wed, 29 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 29 Jul 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Undici
Undici undici
Vendors & Products Undici
Undici undici

Wed, 29 Jul 2026 16:45:00 +0000

Type Values Removed Values Added
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.
Title undici vulnerable to cross-user information disclosure and parse-time crash via degenerate private cache directives
Weaknesses CWE-200
CWE-248
CWE-525
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-07-29T17:53:57.335Z

Reserved: 2026-06-29T11:30:50.679Z

Link: CVE-2026-13697

cve-icon Vulnrichment

Updated: 2026-07-29T17:53:51.109Z

cve-icon NVD

Status : Analyzed

Published: 2026-07-29T17:16:50.503

Modified: 2026-08-04T14:17:59.003

Link: CVE-2026-13697

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-29T16:32:39Z

Links: CVE-2026-13697 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T14:30:05Z

Weaknesses
  • CWE-200

    Exposure of Sensitive Information to an Unauthorized Actor

  • CWE-248

    Uncaught Exception

  • CWE-524

    Use of Cache Containing Sensitive Information

  • CWE-525

    Use of Web Browser Cache Containing Sensitive Information