Vulnerability in hono (CVE-2026-71848)
Summary
Vulnerability in hono (CVE-2026-71848). Risk of unauthorized operations or information disclosure. Exploitable via languageDetector. Mitigation: upgrade to 4.12.34 or later.
Original description
The description as published by the source.
Summary
The languageDetector middleware is vulnerable to algorithmic complexity denial of service when processing a crafted language tag containing a large number of hyphen-separated subtags.
Details
To implement progressive language-tag truncation, normalizeLanguage() repeatedly calls parts.slice(0, i).join('-') for every possible prefix. The total amount of string processing grows quadratically with the number of subtags.
Language values may come from a query parameter, cookie, Accept-Language header, or URL path, depending on the detector configuration. The default detector order enables query-string, cookie, and header detection, so applications using languageDetector() may expose this processing to unauthenticated requests.
Request-size limits reduce the maximum cost of a single request but do not eliminate the issue. Inputs accepted by common JavaScript runtimes can still cause noticeable synchronous event-loop blocking.
Impact
An attacker may repeatedly send requests containing long, hyphen-separated language tags, causing excessive CPU consumption and preventing unrelated requests from being processed.
The practical impact depends on the runtime's request-size limits, reverse-proxy configuration, and the detectors enabled by the application.
Resolution
The progressive lookup should avoid reconstructing every shorter prefix. The implementation can instead inspect the configured supported languages and select the longest value that ma…
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-2026-71848 has been found in hono.
Attackers can target a specific entry point like languageDetector over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade hono to 4.12.34 or later.
If unsure, ask your IT team or search "hono CVE-2026-71848" on the vendor's site.
CVE-2026-71848 (hono) — CWE-407 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: languageDetector
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-407) exists in hono. Attackers reach the vulnerable code path via languageDetector without authentication.
Check the vendor advisory for the affected versions of hono. Attack surface: languageDetector.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
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。