CVE-2026-91920 Details
Description
A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Nov 2, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-91920 | [email protected] | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2528758 | [email protected] |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-444 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 6, 2026 | CVE Modified | [email protected] |
| Nov 3, 2026 | CVE Modified | [email protected] |
| Nov 2, 2026 | CVE Modified | CISA-ADP |
| Oct 30, 2026 | New CVE Received | [email protected] |