Bug 2528758 (CVE-2026-91920)
| Summary: | CVE-2026-91920 undertow: undertow: ChunkReader message length permits chunk-size overflow | ||
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| Product: | [Other] Security Response | Reporter: | Tiago Gamboa Cravo dos Santos Lucas <tgamboac> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | anujha, aschwart, asoldano, aszczucz, bbaranow, bmaxwell, boliveir, bstansbe, dlofthou, drichtar, fmariani, gmalinko, istudens, ivassile, iweiss, janstey, jwon, mcarlett, mosmerov, mposolda, msvehla, nwallace, pberan, pdelbell, pesilva, pjindal, pmackay, rhel-process-autobot, rmartinc, rstancel, rstepani, security-response-team, ssilvert, sthorger, tcunning, thjenkin, vdosoudi, vmuzikar, watson-tool-maintainers, yfang |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
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.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
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Description
Tiago Gamboa Cravo dos Santos Lucas
2026-09-04 17:23:58 UTC
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