CVE-2022-29361Network attack vector

Request smuggling via undrained request bodies

Published May 24, 2022 · Updated Aug 3, 2024

HTTP request smuggling in Pallets Werkzeug 2.1.0 and earlier allows remote attackers to inject a second request through one request body. Python's HTTP server leaves unread body bytes on the persistent connection, so it parses them as the next request when an application does not consume the body. The disputed behavior requires development mode, HTTP/1.1 keep-alive, an unread body, and an HTTP server outside Werkzeug; the injected request can bypass front-end interpretation.

CVSS severity9.8
Critical
EPSS probability8.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request smuggling in Pallets Werkzeug 2.1.0 and earlier allows remote attackers to inject a second request through one request body. Python's HTTP server leaves unread body bytes on the persistent connection, so it parses them as the next request when an application does not consume the body. The disputed behavior requires development mode, HTTP/1.1 keep-alive, an unread body, and an HTTP server outside Werkzeug; the injected request can bypass front-end interpretation.

The record

CVE
CVE-2022-29361
Published
May 24, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC-33HTTP Request Smuggling
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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