VulnerabilityPublished 12 Nov 2026

CVE-2026-126355: honojs hono · Cross-Site Request Forgery

Affects honojs honoSource CVE Database V5

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

Data as of 12 Nov 2026, 22:37 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:H/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 honojs hono to 4.13.16.

Affected software

Product	Affected	Fixed in
honojshono	Affected <4.13.16	Fixed in 4.13.16

AI-suggested

Upgrade Hono to version 4.13.16 or later, where this vulnerability is fixed. The fix restricts the request body validation to relevant state-changing endpoints and properly validates cross-origin requests. No additional mitigation is required if the upgrade is applied.

Description

CVE-2026-126355 is a Cross-Site Request Forgery (CSRF) vulnerability in the Hono JavaScript web application framework prior to version 4.13.16. The csrf() middleware did not validate certain text/ping requests generated by Chromium hyperlink auditing, allowing Chrome and Edge browsers to send cross-origin credentialed POST requests without CORS preflight checks. This could lead to unauthorized state-changing actions if the user's cookie is sent with the request. The issue is fixed in version 4.13.16 by limiting the request body validation to specific endpoints.

Impact

An attacker can exploit this vulnerability to perform unauthorized state-changing operations on behalf of an authenticated user by leveraging cross-origin POST requests sent via Chromium hyperlink auditing pings. This could lead to integrity violations in affected applications using vulnerable versions of Hono. The attack requires the victim's browser to send cookies with the request, which depends on cookie SameSite settings and browser behavior. There is no impact on confidentiality or availability.

Summary

Hono versions before 4.13.16 contain a CSRF vulnerability due to the csrf() middleware only validating origins for content types typically sent by HTML forms. Chromium browsers can exploit this by sending cross-origin credentialed POST requests via hyperlink auditing pings, bypassing Origin and Sec-Fetch-Site checks. The vulnerability requires the user's cookie to be sent, which generally necessitates a same-site origin or a cookie configured with SameSite=None. Firefox is not affected by this attack vector as it does not send hyperlink-auditing pings by default. The vulnerability is addressed in version 4.13.16 by restricting the request body validation to state-changing endpoints identified by path or query string rather than body content.

CWE-352Cross-Site Request Forgery (opens in a new tab)
Compound weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #3OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
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.
Implementation
Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
Architecture and Design
Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).
OWASP Cheat Sheets
REST Assessment (opens in a new tab)
REST Security (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
Insecure Direct Object Reference Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.2.3 (opens in a new tab)
V4.2.2 (opens in a new tab)
V13.3.2 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cross-Domain Search Timing (opens in a new tab)
Cross Site Identification (opens in a new tab)
Cross Site Request Forgery (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 12 Nov 2026, 22:37 UTC

WeaknessesCWE-352

Technical details

References

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