CVE-2026-44456
ADVISORY - githubSummary
Summary
bodyLimit() does not reliably enforce maxSize for requests without a usable Content-Length (e.g. Transfer-Encoding: chunked). Oversized requests can reach handlers and return 200 instead of 413.
Details
For chunked / unknown-length requests, bodyLimit() wraps the body in a stream that counts bytes asynchronously, then runs the handler before the size decision is final. The 413 is only applied afterwards by checking c.error.
This lets the limit be bypassed when:
- the handler does not read the body,
- the handler reads only the first chunk(s) and returns, or
- the handler reads the body but swallows the read error in
try/catch.
In all three cases the handler returns 200 before the limit check completes (or its result is observed).
The fix is to enforce the size decision before next() runs, instead of retrofitting the response via c.error afterwards.
Impact
Applications relying on bodyLimit() as a hard boundary can be bypassed: oversized chunked requests can reach handler logic and return successful responses. Per-request data exposure is bounded by maxSize, but the documented guarantee — "oversized requests are rejected before business logic runs" — does not hold.
Credits
- @lalalala5678 (slow chunked / early return variants)
- @Jvr2022 (error handling bypass)
Common Weakness Enumeration (CWE)
Uncontrolled Resource Consumption
GitHub
3.9
CVSS SCORE
6.5medium| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| hono | npm | - | - | <4.12.16 | 4.12.16 |
CVSS:3 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.
The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
The vulnerable system can be exploited without interaction from any user.
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.
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.
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.
There is no impact to availability within the impacted component.
Chainguard
CGA-v5r8-hq9w-74fr
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