CVE-2023-46136

Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

HIGH
7.5
CVSS Score
Published: October 24, 2023 at 11:48 PM UTC
Updated: June 17, 2026 at 06:30 AM UTC
2 products affected across 2 vendorsWerkzeugWerkzeug

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Severity
HIGH7.5
Exploit prediction
EPSS 1%

Description

Werkzeug is a comprehensive WSGI web application library. If an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.3.83.0.0
Affected range stops below 2.3.8, so it looks safe — our inference, not a vendor statement
v < 2.3.8v < 3.0.1
Affected range stops below 2.3.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.0.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400CWE-407CWE-787

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