CVE-2026-24398VulnerabilityPublished 27 Jan 2026

CVE-2026-24398: honojs hono · Incorrect Regular Expression

Affects honojs honoSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium : upgrade to 4.11.7 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

4.8Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.11.7

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
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: 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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 27 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-26.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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 4.11.7.

Affected software

Product	Affected	Fixed in
honojshono	Affected <4.11.7	Fixed in 4.11.7
npmhono`pkg:npm/hono`Other threats	Affected <4.11.7	Fixed in 4.11.7

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

AI-suggested

European organizations using the Hono framework should immediately upgrade to version 4.11.7 or later to apply the official patch that corrects the IP validation logic. Until upgrading, organizations should consider implementing additional layers of access control beyond IP-based restrictions, such as authentication tokens, VPNs, or zero-trust network access models. Security teams should audit existing IP restriction configurations to identify any reliance on vulnerable versions of Hono and monitor logs for anomalous IP address patterns that may indicate exploitation attempts. Application-level input validation can be enhanced to reject malformed IP addresses before they reach the middleware. Additionally, network-level controls such as firewall rules and intrusion detection systems should be reviewed to detect and block suspicious IP formats. Regular vulnerability scanning and penetration testing focused on IP validation mechanisms can help identify residual risks.

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.11.7, IP Restriction Middleware in Hono is vulnerable to an IP address validation bypass. The `IPV4_REGEX` pattern and `convertIPv4ToBinary` function in `src/utils/ipaddr.ts` do not properly validate that IPv4 octet values are within the valid range of 0-255, allowing attackers to craft malformed IP addresses that bypass IP-based access controls. Version 4.11.7 contains a patch for the issue.

Impact

For European organizations, this vulnerability could lead to unauthorized access to internal or restricted web application endpoints protected by IP-based access controls implemented using Hono framework versions prior to 4.11.7. Attackers could bypass these restrictions by crafting specially malformed IP addresses, potentially exposing sensitive data or internal services. This risk is particularly relevant for organizations that rely heavily on IP whitelisting for security, such as financial institutions, government agencies, and enterprises with strict network segmentation policies. While the impact on confidentiality and integrity is rated low to medium, the ability to circumvent access controls can facilitate further attacks or data leakage. The medium CVSS score reflects the higher complexity of exploitation and the absence of known active exploits, but the threat remains significant for environments where IP restrictions are a primary security mechanism.

CWE-185Incorrect Regular Expression (opens in a new tab)
Class weakness
The product specifies a regular expression in a way that causes data to be improperly matched or compared.
Implementation · Refactoring
Regular expressions can become error prone when defining a complex language even for those experienced in writing grammars. Determine if several smaller regular expressions simplify one large regular expression.
Attack patterns
Command Delimiters (opens in a new tab)
Argument Injection (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Jan 2026, 19:35 UTC

WeaknessesCWE-185

Technical details

References

Community reviews

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