Description
Werkzeug is a Web Server Gateway Interface web application library. Applications using `werkzeug.formparser.MultiPartParser` corresponding to a version of Werkzeug prior to 3.0.6 to parse `multipart/form-data` requests (e.g. all flask applications) are vulnerable to a relatively simple but effective resource exhaustion (denial of service) attack. A specifically crafted form submission request can cause the parser to allocate and block 3 to 8 times the upload size in main memory. There is no upper limit; a single upload at 1 Gbit/s can exhaust 32 GB of RAM in less than 60 seconds. Werkzeug version 3.0.6 fixes this issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| pallets | werkzeug | >= 2.0.0rc1, < 3.0.6 | — |
| pallets | Quart | < 0.20.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-werkzeug | 3.1.3-2 | — |
| Debian 14 | quart | 0.19.9-1 | — |
| Debian 13 | python-werkzeug | 3.1.3-2 | — |
| Debian 13 | quart | 0.19.9-1 | — |
| Debian 12 | python-werkzeug | 2.2.2-3+deb12u1 | — |
| Debian 12 | quart | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | quart | No fix yet | — |
| Ubuntu 25.10 | quart | No fix yet | — |
| Ubuntu 24.04 LTS | python-werkzeug | 3.0.1-3ubuntu0.2 | USN-7093-1 |
| Ubuntu 24.04 LTS | quart | No fix yet | — |
| Ubuntu 22.04 LTS | python-werkzeug | 2.0.2+dfsg1-1ubuntu0.22.04.3 | USN-7093-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 3 | python-Werkzeug | 2.3.6-150400.6.12.1 | SUSE-SU-2024:3810-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-Werkzeug | 3.0.6-1.1 | openSUSE-SU-2026:11943-1, openSUSE-SU-2024:14437-1 |
| openSUSE Leap 15.6 | python-Werkzeug | 2.3.6-150400.6.12.1 | SUSE-SU-2024:3810-1 |
| openSUSE Leap 15.5 | python-Werkzeug | 2.3.6-150400.6.12.1 | SUSE-SU-2024:3810-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | py3-werkzeug | 3.0.6-r0 | — |
| Alpine v3.23 | py3-werkzeug | 3.0.6-r0 | — |
| Alpine v3.22 | py3-werkzeug | 3.0.6-r0 | — |
| Alpine v3.21 | py3-werkzeug | 3.0.6-r0 | — |
| Alpine v3.20 | py3-werkzeug | 3.0.6-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-werkzeug | 3.0.3-2 | — |
| Azure Linux 2 (CBL-Mariner) | python-werkzeug | 2.3.7-3 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | airflow +1 | No fix yet | — |
| Wolfi rolling | airflow-3 | 3.2.0-r0 | — |
| Wolfi rolling | emissary +6 | 3.9.1-r4 | — |
| Wolfi rolling | kubeflow-jupyter-web-app +1 | 1.9.2-r1 | — |
| Wolfi rolling | kubeflow-pipelines-visualization-server | 2.4.0-r0 | — |
| Wolfi rolling | py3-werkzeug | 3.0.6-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | quart | < 0.20.0 | 0.20.0 | GHSA-q34m-jh98-gwm2 |
| PyPI | werkzeug | >= 2.0.0rc1, < 3.0.6 | 3.0.6 | GHSA-q34m-jh98-gwm2 |
Advisories 10
- openSUSE-SU-2026:11943-1 python313-Werkzeug-3.1.9-1.1 on GA media SUSE / openSUSE Security Updates · Oct 2, 2026
- WID-SEC-2025-1559 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2025-0823 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2025-0148 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- USN-7093-1 python-werkzeug vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2024:14437-1 python310-Werkzeug-3.0.6-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:3810-1 Security update for python-Werkzeug SUSE / openSUSE Security Updates · Feb 4, 2026
- NCSC-2025-0124 Kwetsbaarheden verholpen in Oracle Communications NCSC-NL (Netherlands) · Apr 16, 2025
- NCSC-2025-0021 Kwetsbaarheden verholpen in Oracle Communications NCSC-NL (Netherlands) · Jan 22, 2025
- WID-SEC-2024-3614 IBM InfoSphere Information Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Dec 4, 2024
References
- https://github.com/pallets/werkzeug/security/advisories/GHSA-q34m-jh98-gwm2
- https://github.com/pallets/quart/commit/5e78c4169b8eb66b91ead3e62d44721b9e1644ee
- https://github.com/pallets/quart/commit/abb04a512496206de279225340ed022852fbf51f
- https://github.com/pallets/werkzeug/commit/50cfeebcb0727e18cc52ffbeb125f4a66551179b
- https://github.com/pallets/werkzeug/releases/tag/3.0.6