CVE-2023-46136 [High] | Denial of Service in Werkzeug

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.88%	1.06%	+0.19%
2	2026-05-29	1.06%	0.88%	-0.19%
3	2026-05-25	—	1.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.88%

1.06%

+0.19%

2026-05-29

1.06%

0.88%

-0.19%

2026-05-25

—

1.06%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.0	3.1	HIGH	`CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. 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:L) A normal user session is enough; they don’t have to be admin. 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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.1	5.9	[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]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.0

3.1

HIGH

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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:L): A normal user session is enough; they don’t have to be admin.
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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.1

5.9

[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-2023-46136

GitHub Security Advisory for CVE-2023-46136

GHSA-hrfv-mqp8-q5rw · Severity: medium · Ecosystem: pip — Werkzeug DoS: High resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

OS Trackers for CVE-2023-46136

vendor	priority	summary	link
`alpine`	—	CVE-2023-46136: 1 source package rows (py3-werkzeug); 7 state rows across 7 repos (3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community, edge-main); fixed 7, open 0.	https://security.alpinelinux.org/vuln/CVE-2023-46136
`debian`	unimportant	CVE-2023-46136 unimportant 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-2023-46136
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2023-46136
`suse`	high	CVE-2023-46136 severity important: SUSE including 8 source package names (python-Werkzeug, python2-Werkzeug, …), 60 product×package rows across 36 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (36 product lines)): Known Not Affected 49, Fixed 11.	https://www.suse.com/security/cve/CVE-2023-46136/
`ubuntu`	medium	CVE-2023-46136 medium priority: Ubuntu including 1 source packages (werkzeug), 8 status rows across 8 suites (bionic, focal, jammy, lunar, mantic, trusty, upstream, xenial): DNE 4, ignored 3, needs-triage 1.	https://ubuntu.com/security/CVE-2023-46136

Affected software / configurations for CVE-2023-46136

Vendor	Product	Version	Raw CPE
palletsprojects	werkzeug	< 2.3.8	cpe:2.3:a:palletsprojects:werkzeug::::::::
palletsprojects	werkzeug	3.0.0	cpe:2.3:a:palletsprojects:werkzeug:3.0.0:::::::*

References for CVE-2023-46136

URL	Tags
https://github.com/pallets/werkzeug/commit/f3c803b3ade485a45f12b6d6617595350c0f03e2	Patch
https://github.com/pallets/werkzeug/security/advisories/GHSA-hrfv-mqp8-q5rw	Vendor Advisory
https://security.netapp.com/advisory/ntap-20231124-0008/	Third Party Advisory

URL

CVE-2023-46136 | Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

Exploit prediction scoring system (EPSS) score for CVE-2023-46136

Common vulnerability scoring system (CVSS) metrics for CVE-2023-46136

Weakness enumeration for CVE-2023-46136

GitHub Security Advisory for CVE-2023-46136

OS Trackers for CVE-2023-46136

Affected software / configurations for CVE-2023-46136

References for CVE-2023-46136