CVE-2026-71848

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/honojs/hono/commit/f70e2c31684387b3231cc38512a31df6ca76a1c7
https://github.com/honojs/hono/releases/tag/v4.12.34
https://github.com/honojs/hono/security/advisories/GHSA-54fx-42gc-7vw4

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-07 19:18

Updated : 2026-09-09 21:02

NVD link : CVE-2026-71848

Mitre link : CVE-2026-71848

CVE.ORG link : CVE-2026-71848

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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