CVE-2026-103866

Apache Sling Engine: Hand-rolled parameter parser diverges from RFC/container parsing, enabling smuggling

Published Nov 5, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling') vulnerability in Apache Sling Engine. The engine's query/form parser accepts non-standard percent-escapes, wrong charsets, and continues request processing on such errors.



This issue affects Apache Sling Engine: before 3.0.4.



Users are recommended to upgrade to version 3.0.4, which fixes the issue.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}

threat_severity

Low

Type Values Removed Values Added
First Time appeared Apache
Apache apache Sling Engine
Vendors & Products Apache
Apache apache Sling Engine
Type Values Removed Values Added
Description Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling') vulnerability in Apache Sling Engine. The engine's query/form parser accepts non-standard percent-escapes, wrong charsets, and continues request processing on such errors. This issue affects Apache Sling Engine: before 3.0.4. Users are recommended to upgrade to version 3.0.4, which fixes the issue.
Title Apache Sling Engine: Hand-rolled parameter parser diverges from RFC/container parsing, enabling smuggling
Weaknesses CWE-436
CWE-444
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Nov 10, 2026, 3:55 PM
Reserved
Oct 1, 2026, 11:47 AM
Status
Awaiting Analysis
Published
Nov 5, 2026, 1:17 PM
Modified
Nov 12, 2026, 5:06 PM
Severity
Low
Public date
Nov 5, 2026, 12:33 PM