# CVE-2026-48710: Kludex Starlette HTTP Request/Response Smuggling > Attackers can bypass path-based security checks in Starlette applications by sending a malformed Host header that poisons the reconstructed request URL. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`) - **Exploited in the wild:** Yes, since 2 Sep 2026 (CISA KEV) - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 26 May 2026 - **Updated:** 1 Oct 2026 - **Also known as:** CLEANSTART-2026-FT89883, CLSA-2026-1781052728, CLSA-2026-1789648460, DEBIAN-CVE-2026-48710, ECHO-8103-2b4d-a762, GHSA-86qp-5c8j-p5mr, MINI-2fh3-9x8p-7695, MINI-3wr7-25wj-mvwh, MINI-62xj-rx29-wwv5, MINI-65v2-9wp6-rcm2, MINI-6q84-j25v-j4qm, MINI-76vr-gm9x-7v6q, MINI-96mf-2m6r-mmvw, MINI-9v8h-8r44-w88x, MINI-fvvx-8399-97j4, MINI-fwf6-6qvj-c6hx, MINI-g76q-r358-6xq5, MINI-p8m5-2hq4-w3rr, MINI-q58q-mjj6-fjc3, MINI-r6x2-6pgh-mxgh, MINI-rc7p-w479-97f2, MINI-v36h-2cxq-ww56, MINI-vhxq-7hch-cpm5, MINI-vwcp-qw56-3cwm, PYSEC-2026-161, ROOT-APP-PYPI-CVE-2026-48710, UBUNTU-CVE-2026-48710, X41-2026-002, openSUSE-SU-2026:11026-1, openSUSE-SU-2026:11044-1 ## What is CVE-2026-48710? CVE-2026-48710 is a medium-severity vulnerability in Redhat Satellite, published on 26 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values. Weakness: CWE-1289 (Improper Validation of Unsafe Equivalence in Input), CWE-444 (Inconsistent Interpretation of HTTP Requests) ## Which versions are affected by CVE-2026-48710? 3 open source packages ship an affected version, including starlette. It affects 8 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `starlette` | PyPI | All versions | 1.0.1 | | `starlette` | PyPI | All versions | 1.0.1 | | `starlette` | PyPI | All versions | 1.0.1 | | `python-google-adk` | openSUSE:Tumbleweed | All versions | 2.2.0-1.1 | | `python-starlette` | openSUSE:Tumbleweed | All versions | 1.2.0-1.1 | Products: Encode Starlette, Redhat Ai Inference Server, Redhat Ansible Automation Platform, Redhat Enterprise Linux Ai, Redhat Migration Toolkit for Applications, Redhat Openshift Ai, Redhat Openshift Lightspeed, Redhat Satellite. ## How do I fix CVE-2026-48710? Upgrade starlette to 1.0.1 or later. US federal agencies must fix it by 16 Sep 2026. ## Is CVE-2026-48710 being exploited? Yes. Attackers have exploited CVE-2026-48710 in the wild since at least 2 Sep 2026. Public exploit code: - Detect, assess, and respond to supply chain attacks across npm/yarn and Python (pip/poetry/uv). Claude Code skill + standalone scripts. Built during axios RAT (2026-03-31) and Starlette BadHost CVE-2026-48710 (2026-05-22). (github_poc): https://github.com/eris-ths/supply-chain-guard - Starlette Host-Header URL Confusion Lab (X41-2026-002) - CVE-2026-48710 (github_poc): https://github.com/xtremebeing/starlette-host-header-lab - Detection scanner for CVE-2026-48710 - Host-header auth bypass in Starlette/FastAPI (github_poc): https://github.com/Bhanunamikaze/BadHost-CVE-2026-48710-Exploit - OXDEV-77637 repro fixture: uv workspace whose transitive CVE (starlette 0.25.0 / CVE-2026-48710) is dropped when the lean clone omits workspace-member pyproject.toml. Tag: repro-OXDEV-77637 (github_poc): https://github.com/sb-ox/repro-OXDEV-77637-uv-workspace - CVE-2026-48710漏洞验证代码 (github_poc): https://github.com/CuteeCat/CVE-2026-48710 - Starlette - Improper Validation of Unsafe Equivalence in Input (nuclei): http/cves/2026/CVE-2026-48710.yaml ## Other vulnerabilities in Redhat Satellite - [CVE-2026-54283](https://insights.sbomify.com/CVE-2026-54283/): Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS (high 7.5) - [CVE-2026-48818](https://insights.sbomify.com/CVE-2026-48818/): Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows (high 7.5) - [CVE-2023-29159](https://insights.sbomify.com/CVE-2023-29159/): Starlette has Path Traversal vulnerability in StaticFiles (high 7.5) - [CVE-2023-30798](https://insights.sbomify.com/CVE-2023-30798/): MultipartParser DOS with too many fields or files in Starlette Framework (high 7.5) - [CVE-2026-48817](https://insights.sbomify.com/CVE-2026-48817/): Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr` (medium 5.3) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-48710 and fix it if it is affected. What it is: CVE-2026-48710 is a medium-severity vulnerability in Redhat Satellite, published on 26 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: Yes. Attackers have exploited CVE-2026-48710 in the wild since at least 2 Sep 2026. Affected packages and fixed versions: - starlette (PyPI): affected all versions; fixed in 1.0.1 - starlette (PyPI): affected all versions; fixed in 1.0.1 - starlette (PyPI): affected all versions; fixed in 1.0.1 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-48710/ (Markdown: https://insights.sbomify.com/CVE-2026-48710/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48710 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48710 - OSV: https://osv.dev/vulnerability/CVE-2026-48710 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-48710/ Summaries are generated and may contain mistakes; the official description above is the record.