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TI-2026-50177 Aliases CVE-2026-71848GHSA-54fx-42gc-7vw4

Hono: Algorithmic Complexity DoS in Language Middleware

Priority LOW 31CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-407.

Summary

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.12.0 to 4.12.33, 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. To implement progressive language tag truncation, normalizeLanguage() repeatedly calls parts.slice(0, i).join('-') for every possible prefix, so 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, and the default detector order enables query string, cookie, and header detection, so applications using languageDetector() may expose this processing to unauthenticated requests. An attacker may repeatedly send requests containing long, hyphen separated language tags, causing excessive CPU consumption and preventing unrelated requests from being processed. This issue is fixed in version 4.12.34.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00507 43rd percentileScored 2026-11-07
Fix Fixed hono (honojs): 4.12.34hono (npm): 4.12.34

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
honojshono4.12.0 to before 4.12.344.12.34Patch availableCNA
—hono (npm)4.12.0 to before 4.12.344.12.34Patch availableGHSA-54fx-42gc-7vw4
  • hono Vendorhonojs Affected 4.12.0 to before 4.12.34 Fixed in 4.12.34 Patch available CNA
  • hono (npm) Vendor— Affected 4.12.0 to before 4.12.34 Fixed in 4.12.34 Patch available GHSA-54fx-42gc-7vw4

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:hono:hono:*:*:*:*:*:*:*:*——honojs
  • cpe:2.3:a:hono:hono:*:*:*:*:*:*:*:* Versions — — ·honojs

Remediation

  • Fix · CNA hono (honojs) Fixed in 4.12.34
  • Fix · GHSA-54fx-42gc-7vw4 hono (npm) Fixed in 4.12.34 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-71848
  2. 2026-10-03 Alias added: GHSA-54fx-42gc-7vw4

References

Other 4

  • TI-2024-21741 Hono vulnerable to Restricted Directory Traversal in serveStatic with deno CVSS 3.1MEDIUM 5.3
  • TI-2024-15441 @hono/node-server can't handle "double dots" in URL CVSS 3.1MEDIUM 5.3
  • TI-2024-32610 Hono vulnerable to bypass of CSRF Middleware by a request without Content-Type header. CVSS 3.1MEDIUM 5.9
  • TI-2024-29381 Hono CSRF middleware can be bypassed using crafted Content-Type header CVSS 3.1MEDIUM 5.0
  • TI-2026-39189 Hono: Lambda@Edge adapter keeps only the last value of a repeated request header, dropping the rest CVSS 3.1MEDIUM 4.8
  • TI-2026-23190 Hono: Arbitrary file access via serveStatic vulnerability CVSS 3.1CRITICAL 9.8
See all 59 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences