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Public proof of conceptFix available

CVE-2023-46136

A public proof of concept exists; no exploitation attested.

  • Published2023-10-25
  • Fixed in3.0.1 · 2.3.8
  • WeaknessCWE-400 · CWE-407 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2023-10-2518:17CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-46136?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-46136?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD
Palletsprojects werkzeug
BranchAffectedFixed in
3.0≥ 3.0.0, < 3.0.13.0.1
2.3< 2.3.82.3.8
2.x≥ 2.0.0rc1, < 2.3.82.3.8
3.0= 3.0.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • RHSA-2023:7610 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.12.45 packages and security update

Full record on NVD

Fix

  1. Update Palletsprojects werkzeug to 3.0.1 · 2.3.8
  2. Vendor fix Red Hat Product Security RHSA-2023:7610 · 2 productsFor OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.12/release_notes/ocp-4-1…

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedJawadPy/WerkGhost
PoC-in-GitHub

Sources

  • CNACVSS 3.18read 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-400, CWE-407read 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score1.1 %2026-10-23
  • PoC-in-GitHubproof of concept1read 2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2023-10-25
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is 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.

Is CVE-2023-46136 actively exploited?

Active exploitation of CVE-2023-46136 has not been confirmed. Its EPSS score was 1.1% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-46136?

CVE-2023-46136 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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