# CVE-2026-103866: Apache Sling Engine: Hand-rolled parameter parser diverges from RFC/container parsing, enabling smuggling

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

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 remediation reported in collected sources

## Affected products and versions

- Apache Software Foundation / Apache Sling Engine: ≥ 0; < 3.0.4 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-436, CWE-444

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://lists.apache.org/thread.html/yoftbty2lc7kmtldmyvj7w0m0n1ncbf6 (CNA: apache; vendor-advisory)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2026-103866; retrieved 2026-11-05; source updated 2026-11-05

Revision: 17cfee17cc775c413c5f08a4b5a5d10cdb610572375a3965fdd7252e13222b33

Canonical: https://y2.dev/cve/CVE-2026-103866

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