PYSEC-2026-161

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Import Source
https://github.com/pypa/advisory-database/blob/main/vulns/starlette/PYSEC-2026-161.yaml
JSON Data
https://api.osv.dev/v1/vulns/PYSEC-2026-161
Aliases
Published
2026-05-22T13:11:38.659740Z
Modified
2026-05-26T15:41:31.112064345Z
Summary
BadHost: Missing Host header validation poisons request.url.path, bypassing path-based security checks
Details

Starlette reconstructs the requested URL based on the HTTP Host request header and requested path, but does not perform any validation of the Host header value. This allows attackers to inject paths into the host part, prepending the actual path. However, routing in Starlette is based on the actual request path. This inconsistent interpretation of HTTP requests may lead to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path.

References

Affected packages

PyPI / starlette

Package

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.0.1

Affected versions

0.*
0.1.0
0.1.1
0.1.2
0.1.3
0.1.4
0.1.5
0.1.6
0.1.7
0.1.8
0.1.9
0.1.10
0.1.11
0.1.12
0.1.13
0.1.14
0.1.15
0.1.16
0.1.17
0.2.0
0.2.1
0.2.2
0.2.3
0.3.0
0.3.1
0.3.2
0.3.3
0.3.4
0.3.5
0.3.6
0.3.7
0.4.0
0.4.1
0.4.2
0.5.0
0.5.1
0.5.2
0.5.3
0.5.4
0.5.5
0.6.0
0.6.1
0.6.2
0.6.3
0.7.0
0.7.1
0.7.2
0.7.3
0.7.4
0.8.0
0.8.1
0.8.2
0.8.3
0.8.4
0.8.5
0.8.6
0.8.7
0.8.8
0.9.0
0.9.1
0.9.2
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
0.9.10
0.9.11
0.10.0
0.10.1
0.10.2
0.10.3
0.10.4
0.10.5
0.10.6
0.10.7
0.11.0
0.11.1
0.11.2
0.11.3
0.11.4
0.12.0b1
0.12.0b2
0.12.0b3
0.12.0
0.12.1
0.12.2
0.12.3
0.12.4
0.12.5
0.12.6
0.12.7
0.12.8
0.12.9
0.12.10
0.12.11
0.12.12
0.12.13
0.13.0
0.13.1
0.13.2
0.13.3
0.13.4
0.13.5
0.13.6
0.13.7
0.13.8
0.14.0
0.14.1
0.14.2
0.15.0
0.16.0
0.17.0
0.17.1
0.18.0
0.19.0
0.19.1
0.20.0
0.20.1
0.20.2
0.20.3
0.20.4
0.21.0
0.22.0
0.23.0
0.23.1
0.24.0
0.25.0
0.26.0
0.26.0.post1
0.26.1
0.27.0
0.28.0
0.29.0
0.30.0
0.31.0
0.31.1
0.32.0
0.32.0.post1
0.33.0
0.34.0
0.35.0
0.35.1
0.36.0
0.36.1
0.36.2
0.36.3
0.37.0
0.37.1
0.37.2
0.38.0
0.38.1
0.38.2
0.38.3
0.38.4
0.38.5
0.38.6
0.39.0
0.39.1
0.39.2
0.40.0
0.41.0
0.41.1
0.41.2
0.41.3
0.42.0
0.43.0
0.44.0
0.45.0
0.45.1
0.45.2
0.45.3
0.46.0
0.46.1
0.46.2
0.47.0
0.47.1
0.47.2
0.47.3
0.48.0
0.49.0
0.49.1
0.49.2
0.49.3
0.50.0
0.51.0
0.52.0
0.52.1
1.*
1.0.0rc1
1.0.0

Database specific

source
"https://github.com/pypa/advisory-database/blob/main/vulns/starlette/PYSEC-2026-161.yaml"