Vulnerability in hono (CVE-2026-71850)
Summary
Vulnerability in hono (CVE-2026-71850). Confidential information can be exposed externally. Mitigation: upgrade to 4.12.34 or later.
Original description
The description as published by the source.
Summary
memo() from hono/jsx retains the result of a server-side render and reuses it for later renders with comparator-equal props. Request-scoped values read inside the component take no part in that comparison, so a response can contain HTML rendered for another user's request.
Details
Components wrapped with memo() are compared by props alone. Values read implicitly during rendering do not participate: JSX Context through createContext() and useContext(), useRequestContext() from hono/jsx-renderer, and getContext() from hono/context-storage. The retained result lives as long as the wrapped component, so it outlives the request that produced it.
Per-request context isolation is not what fails: the current request's values are established correctly, but the memoized component is skipped before anything reads them.
This issue arises when a component wrapped in memo() obtains user- or request-specific data from an ambient context instead of through props.
Impact
A user may receive a response containing HTML rendered for another user, when both render the same memoized component with comparator-equal props on the same warm instance.
This may lead to:
- Disclosure of another user's account or profile data
- Disclosure of request-scoped secrets embedded in HTML, such as CSRF tokens
- Exposure of role-specific content to users who should not receive it
Exploitation depends on the order in which renders populate the retained value and on b…
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-2026-71850 has been found in hono.
Confidential information can be exposed externally. CVSS score: 4.8/10.
What to do: upgrade hono to 4.12.34 or later.
If unsure, ask your IT team or search "hono CVE-2026-71850" on the vendor's site.
CVE-2026-71850 (hono) — CWE-488 / CVSS v3 4.8
Attack vector: remote (network-reachable)
Patched: 4.12.34 — 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-488) exists in hono.
Check the vendor advisory for the affected versions of hono.
Severity: Medium (CVSS 4.8/10). Confidential information can be exposed externally.
Update to 4.12.34.
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 'hono' . 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
-
1Identify exposure identify
grep -r 'hono' . | 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
hono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 hono to 4.12.34ステージング環境で 4.12.34 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
References
- web security-advisories@github.com
- web github.com
- web github.com
- web github.com