CVE-2026-91920 (GCVE-0-2026-91920)

Vulnerability from cvelistv5 – Published: 2026-10-30 01:16 – Updated: 2026-11-06 01:46
VLAI
Title
Undertow: undertow: chunkreader message length permits chunk-size overflow
Summary
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-11-02 20:40 UTC
CWE
  • CWE-444 - Inconsistent Interpretation of HTTP Requests
Assigner
redhat CNA
References
URL Tags
https://access.redhat.com/security/cve/CVE-2026-91920 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2528758 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-10-29 12:11
Credits
Red Hat would like to thank Arpit Jain for reporting this issue.
Show details on NVD website
To clipboard 

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