Vulnerability · Published Nov 5, 2026 · Assigned by apache
CVE-2026-103866Apache Sling Engine: Hand-rolled parameter parser diverges from RFC/container parsing, enabling smuggling
Unrated
In plain English
A security flaw in Apache Sling Engine from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).
Severity (CVSS )–Not rated
Exploit odds (30 days)0.2%top 88.4% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Sling Engine | 0 – before 3.0.4 |
Weakness: CWE-436, CWE-444