CVE-2026-66338
Libsoup: libsoup: http request smuggling via permissive chunk-size parsing in soup_body_input_stream_read_chunked()
- State
- Published
- Severity
- 5.4 Medium
- Published
- Jul 24, 2026
- Updated
- Jul 27, 2026
- Reserved
- Jul 24, 2026
Description
A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N | redhat |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
Red Hat Enterprise Linux 10Red Hat | |
Red Hat Enterprise Linux 6Red Hat | |
Red Hat Enterprise Linux 7Red Hat | |
Red Hat Enterprise Linux 8Red Hat | |
Red Hat Enterprise Linux 9Red Hat |
References
- https://access.redhat.com/security/cve/CVE-2026-66338vdb-entry
- RHBZ#2506950issue-tracking
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