Service interruption via multipart parser resource exhaustion
Published Oct 24, 2023 · Updated May 20, 2026
Uncontrolled resource consumption in Pallets Werkzeug before 2.3.8 or 3.0.1 allows remote attackers to interrupt services via multipart uploads. The multipart parser inefficiently appends CR- or LF-prefixed file data to a growing bytearray while repeatedly searching for boundaries, causing excessive CPU use and memory growth. An attacker only needs access to an endpoint that parses multipart/form-data; sustained or large requests can block legitimate workers, trigger an out-of-memory kill, or exhaust all workers.
Summary
What happened
Uncontrolled resource consumption in Pallets Werkzeug before 2.3.8 or 3.0.1 allows remote attackers to interrupt services via multipart uploads. The multipart parser inefficiently appends CR- or LF-prefixed file data to a growing bytearray while repeatedly searching for boundaries, causing excessive CPU use and memory growth. An attacker only needs access to an endpoint that parses multipart/form-data; sustained or large requests can block legitimate workers, trigger an out-of-memory kill, or exhaust all workers.
The record
- CVE
- CVE-2023-46136
- Published
- Oct 24, 2023
- Updated
- May 20, 2026
- Vendor
- Pallets
- Product
- Werkzeug
- Classifications
- CWE-400, CWE-787, CWE-407, T1499.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 24, 2023CVE publishedPublication date reported by the CVE source.
- May 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2.0.0rc1, < 2.3.8
- Affected versionversion=>= 3.0.0, < 3.0.1
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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