Vulnerability in Starlette (CVE-2026-54282)
Summary
Vulnerability in Starlette (CVE-2026-54282). Risk of unauthorized operations or information disclosure. Exploitable via Host header. Mitigation: upgrade to 1.3.0 or later.
Original description
The description as published by the source.
Starlette is a lightweight ASGI framework/toolkit. Prior to 1.3.0, the HTTP request path is not validated before being used to reconstruct request.url. Because request.url is rebuilt by concatenating {scheme}://{host}{path} and re-parsing the result, a path that does not begin with / (for example @google.com) moves the authority boundary during re-parsing, so request.url.hostname and request.url.netloc become attacker-controlled. Code that reads request.url.hostname (rather than the Host header or scope) can therefore be misled into trusting an attacker-supplied host. This vulnerability is fixed in 1.3.0.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54282 has been found in Starlette.
Attackers can target a specific entry point like Host header over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.7/10.
What to do: upgrade Starlette to 1.3.0 or later.
If unsure, ask your IT team or search "Starlette CVE-2026-54282" on the vendor's site.
CVE-2026-54282 (Starlette) — CWE-20 / CVSS v3 3.7
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Host header
Patched: 1.3.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in Starlette. Attackers reach the vulnerable code path via Host header without authentication.
Check the vendor advisory for the affected versions of Starlette. Attack surface: Host header.
Severity: Low (CVSS 3.7/10). Risk of unauthorized operations or information disclosure.
Update to 1.3.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Starlette' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'Starlette' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Starletteを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Starlette to 1.3.0ステージング環境で 1.3.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-54282 starlette Fixed in: 0.26.1-1+deb12u2
- Ubuntu UBUNTU-CVE-2026-54282 starlette
References
- advisory github.com
- web github.com
- web nvd.nist.gov
- web github.com