Vulnerability in hyper (CVE-2021-21299)
Summary
Vulnerability in hyper (CVE-2021-21299). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 0.12.36 or later.
Original description
The description as published by the source.
hyper is an open-source HTTP library for Rust (crates.io). In hyper from version 0.12.0 and before versions 0.13.10 and 0.14.3 there is a vulnerability that can enable a request smuggling attack. The HTTP server code had a flaw that incorrectly understands some requests with multiple transfer-encoding headers to have a chunked payload, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that understands the request payload boundary differently can result in "request smuggling" or "desync attacks". To determine if vulnerable, all these things must be true: 1) Using hyper as an HTTP server (the client is not affected), 2) Using HTTP/1.1 (HTTP/2 does not use transfer-encoding), 3) Using a vulnerable HTTP proxy upstream to hyper. If an upstream proxy correctly rejects the illegal transfer-encoding headers, the desync attack cannot succeed. If there is no proxy upstream of hyper, hyper cannot start the desync attack, as the client will repair the headers before forwarding. This is fixed in versions 0.14.3 and 0.13.10. As a workaround one can take the following options: 1) Reject requests that contain a transfer-encoding header, 2) Ensure any upstream proxy handles transfer-encoding correctly.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2021-21299 has been found in hyper.
Successful exploitation can lead to full system takeover.
What to do: upgrade hyper to 0.12.36 or later.
If unsure, ask your IT team or search "hyper CVE-2021-21299" on the vendor's site.
CVE-2021-21299 (hyper) — CWE-444
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 0.12.36 — 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-444) exists in hyper.
Check the vendor advisory for the affected versions of hyper.
Severity: ?. Successful exploitation can lead to full system takeover.
Update to 0.12.36.
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 'hyper' . 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 'hyper' . | 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
hyper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 hyper to 0.12.36ステージング環境で 0.12.36 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。
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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
- Ubuntu UBUNTU-CVE-2021-21299 rust-hyper
References
- advisory github.com
- advisory nvd.nist.gov
- advisory portswigger.net
- advisory rustsec.org
- advisory crates.io
- package github.com
- patch github.com