What is CVE-2023-46136?

CVE-2023-46136 is a high-severity vulnerability in Pallets Werkzeug, classified under Uncontrolled Resource Consumption. CVSS score: 8.0/10. Published 2023-10-25.

How severe is CVE-2023-46136?

High severity. CVSS v3 base score is 8.0 out of 10.

Is CVE-2023-46136 known to be exploited?

5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Pallets Werkzeug

CVE-2023-46136

Werkzeug is a comprehensive WSGI web application library. In versions on the 3.x branch prior to 3.0.1 and on the 2.x branch prior to 2.3.8, 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 and 2.3.8.

Vulnerability class: DoS (Denial of Service)

Published 2023-10-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.0 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.011 (64.4th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Pallets Werkzeug — versions >= 3.0.0, < 3.0.1, >= 2.0.0rc1, < 2.3.8, < 3.0.1
Palletsprojects Werkzeug — versions 3.0.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw (Vendor Advisory)
github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2 (Patch)
af854a3a-2127-422b-91ae-364da2661108 (Third Party Advisory)

Frequently asked questions

What is CVE-2023-46136?: CVE-2023-46136 is a high-severity vulnerability in Pallets Werkzeug, classified under Uncontrolled Resource Consumption. CVSS score: 8.0/10. Published 2023-10-25.
How severe is CVE-2023-46136?: High severity. CVSS v3 base score is 8.0 out of 10.
Is CVE-2023-46136 known to be exploited?: 5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.