CVE-2023-25577 | Werkzeug may allow high resource usage when parsing multipart form data with many fields

Werkzeug is a comprehensive WSGI web application library. Prior to version 2.2.3, Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory as Python data. If a request can be made to an endpoint that accesses `request.data`, `request.form`, `request.files`, or `request.get_data(parse_form_data=False)`, it can cause unexpectedly high resource usage. 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. The amount of RAM required can trigger an out of memory kill of the process. Unlimited file parts can use up memory and file handles. If many concurrent requests are sent continuously, this can exhaust or kill all available workers. Version 2.2.3 contains a patch for this issue.

Published: 2023-02-14 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-25577 is rated Moderate Risk (55.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.42%). EPSS rose +1.05% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-25577

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.37% 1.42% +1.05%
2 2026-03-04 0.33% 0.37% +0.04%
3 2026-01-15 — 0.33% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-25577

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-25577

GitHub Security Advisory for CVE-2023-25577

GHSA-xg9f-g7g7-2323 · Severity: high · Ecosystem: pip — High resource usage when parsing multipart form data with many fields

OS Trackers for CVE-2023-25577

vendor priority summary link
debian not yet assigned CVE-2023-25577 not yet assigned priority: Debian including 1 source packages (python-werkzeug), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-25577
redhat high — https://access.redhat.com/security/cve/CVE-2023-25577
suse high CVE-2023-25577 severity important: SUSE including 51 source package names (1.10.1.16.4.5.392:python3-Werkzeug-1.0.1-150300.3.3.1, 3.8.0.1.0.4.5.4:python3-Werkzeug-1.0.1-150300.3.3.1, …), 125 product×package rows across 49 product lines (Container ses/7.1/cephcsi/cephcsi, Container ses/7.1/rook/ceph, … (49 product lines)): Fixed 125. https://www.suse.com/security/cve/CVE-2023-25577/
ubuntu medium CVE-2023-25577 medium priority: Ubuntu including 1 source packages (python-werkzeug), 8 status rows across 8 suites (bionic, focal, jammy, kinetic, lunar, trusty, upstream, xenial): released 7, ignored 1. https://ubuntu.com/security/CVE-2023-25577

Affected software / configurations for CVE-2023-25577

Vendor Product Version Raw CPE
palletsprojects werkzeug < 2.2.3 cpe:2.3:a:palletsprojects:werkzeug:*:*:*:*:*:*:*:*

References for CVE-2023-25577

cvelogic Threat Intelligence