Description
Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Kludex | starlette | >= 0.4.1, < 1.3.1 | — |
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 | starlette | 1.3.1-1 | — |
| Debian 13 | starlette | 0.46.1-3+deb13u3 | — |
| Debian 12 | starlette | 0.26.1-1+deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | starlette | No fix yet | — |
| Ubuntu 26.04 LTS | starlette | No fix yet | — |
| Ubuntu 25.10 | starlette | No fix yet | — |
| Ubuntu 24.04 LTS | starlette | No fix yet | — |
| Ubuntu 22.04 LTS | starlette | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | python-starlette | 0.41.3-160000.4.1 | SUSE-SU-2026:22360-1 |
| SLES 16.0 | python-starlette | 0.41.3-160000.4.1 | SUSE-SU-2026:22360-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | python-starlette | 0.41.3-160000.4.1 | openSUSE-SU-2026:21053-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | airflow-3 | 3.2.2-r6 | — |
| Wolfi rolling | kserve +1 | 0.20.0-r7 | — |
| Wolfi rolling | kserve-storage-controller | 0.20.0-r4 | — |
| Wolfi rolling | semgrep | 1.167.0-r1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | starlette | >= 0.4.1, < 1.3.1 | 1.3.1 | GHSA-82w8-qh3p-5jfq |
Advisories 2
- SUSE-SU-2026:22360-1 Security update for python-starlette SUSE / openSUSE Security Updates · Jul 2, 2026
- openSUSE-SU-2026:21053-1 Security update for python-starlette SUSE / openSUSE Security Updates · Jun 30, 2026