Bug 2466776 (CVE-2026-5766)

Summary: CVE-2026-5766 django: Django: Service degradation via understated Content-Length header in ASGI requests
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: anthomas, brasmith, caswilli, cmyers, cochase, dnakabaa, dranck, dschmidt, eglynn, ehelms, erezende, ggainey, jjoyce, jlanda, jmitchel, jpasqual, jpretori, jschluet, juwatts, jwong, kaycoth, kshier, lbrazdil, lcouzens, lhh, mburns, mgarciac, mhulan, mminar, nmoumoul, omaciel, osousa, pcreech, rbiba, rchan, simaishi, smallamp, smcdonal, sskracic, stcannon, teagle, tmalecek, tpfromme, ttakamiy, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in Django. This vulnerability allows a remote attacker to bypass the FILE_UPLOAD_MAX_MEMORY_SIZE limit by sending specially crafted ASGI (Asynchronous Server Gateway Interface) requests with a missing or understated Content-Length header. This can lead to large files being loaded into memory, potentially causing service degradation or a Denial of Service (DoS) condition.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2484687    
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Description OSIDB Bzimport 2026-05-05 17:01:59 UTC 
An issue was discovered in 6.0 before 6.0.5 and 5.2 before 5.2.14.
ASGI requests with a missing or understated `Content-Length` header can bypass the `FILE_UPLOAD_MAX_MEMORY_SIZE` limit, potentially loading large files into memory and causing service degradation.
 
As a reminder, Django expects a limit to be configured at the web server level rather than solely relying on `FILE_UPLOAD_MAX_MEMORY_SIZE`.
Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected.
Django would like to thank Kyle Agronick for reporting this issue.