Access-control bypass via case-folded usernames
Published Sep 9, 2026 · Updated Sep 9, 2026
Improper case handling in the CUPS scheduler on affected Red Hat products allows remote authenticated users to bypass username access controls. The check_quotas and cupsdGetPrivateAttrs paths compare request-derived usernames case-insensitively against printer ACL, owner, and explicit-user entries. Exploitation requires affected ACL or private-access settings and can permit print-job submission or disclosure of filtered job or subscription attributes.
Summary
What happened
Improper case handling in the CUPS scheduler on affected Red Hat products allows remote authenticated users to bypass username access controls. The check_quotas and cupsdGetPrivateAttrs paths compare request-derived usernames case-insensitively against printer ACL, owner, and explicit-user entries. Exploitation requires affected ACL or private-access settings and can permit print-job submission or disclosure of filtered job or subscription attributes.
The record
- CVE
- CVE-2026-87876
- Published
- Sep 9, 2026
- Updated
- Sep 9, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 6
- Classifications
- CWE-178, T1078
- Attack vector
- adjacent
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 9, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- OpenPrinting scheduler side-path reproduction patternsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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