CVE-2026-126358VulnerabilityPublished 12 Nov 2026

Hono: RegExpRouter skips wildcard middleware for some route sets and for paths with an encoded line terminator

Affects honoSource GCVE Database

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Authoritative record:CVE-2026-126358· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 4.13.16 when convenient.

Data as of 13 Nov 2026, 00:08 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	5.3

Patch: Available – fixed in 4.13.16

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade hono to 4.13.16.

Affected software

Product	Affected	Fixed in
npmhono	Affected >=4.1.4 <4.13.16	Fixed in 4.13.16

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Hono to version 4.13.16 or later where this issue is fixed. As a workaround before upgrading, use the TrieRouter instead by initializing Hono with `new Hono({ router: new TrieRouter() })` to avoid the RegExpRouter middleware skipping behavior.

Description

Hono's RegExpRouter in versions >=4.1.4 and <4.13.16 has a vulnerability where wildcard middleware is skipped in certain routing scenarios, allowing unauthenticated clients to reach route handlers or the not-found handler without middleware enforcement. This affects applications relying on RegExpRouter or the default SmartRouter for authentication or authorization middleware on wildcard paths. The issue is fixed in version 4.13.16.

Impact

An unauthenticated attacker can bypass authentication or authorization middleware registered on wildcard routes, potentially accessing route handlers or triggering the not-found handler without proper middleware checks. This impacts applications using RegExpRouter or SmartRouter relying on wildcard middleware for security enforcement.

Summary

The RegExpRouter component of Hono, used by default in SmartRouter, improperly skips applying wildcard middleware in three cases: when middleware uses explicit default patterns but routes differ in pattern syntax; when middleware on '/admin/*' is not applied to routes registered as '/admin*'; and when paths contain encoded line terminators, causing no wildcard match and bypassing middleware. This allows unauthenticated access to route handlers or the not-found handler without the intended middleware protections. The fix in 4.13.16 corrects middleware coverage logic, allows wildcards to match line terminators, rejects unsupported empty-string matching patterns, and requires regeneration of PreparedRegExpRouter data.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 00:08 UTC

WeaknessesCWE-863

Technical details

References

Community reviews

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