CVE-2023-46136 — Werkzeug is a comprehensive WSGI web application library

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

01What is this vulnerability?

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…

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-10-25T18:17:36.753
• Last modified: 2026-05-20T23:16:34.553

09References

• github.com — https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f0…
• github.com — https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw
• github.com — https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f0…
• github.com — https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw
• security.netapp.com — https://security.netapp.com/advisory/ntap-20231124-0008/