CVE
Node Server access control bypass in request path parsing
- Exploited
- No known exploitation
- Fix
- Fixed in 2.1.6, 1.19.18
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 2.1.6, 1.19.18.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.38% · 31st percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 42/100 · provisional
- The share of the registry's downloads of each affected package in the window that were versions inside the affected ranges. Downloads, not users or installs: CI runs and mirrors inflate the counts.
- 83% of @hono/node-server downloads last week were affected versions (81.6M).npm, 98.4M downloads in the last 7 days, read Nov 8, 2026
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
@hono/node-server, which runs Hono applications on Node.js, treats a backslash in a request path as a path separator. A remote, unauthenticated attacker can exploit this when a reverse proxy, load balancer, or web application firewall that keeps the backslash applies path-based rules, allowing them to reach routes that the upstream component was meant to block.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
@hono/node-server allows running the Hono application on Node.js. Prior to 1.19.18 and from 2.0.0 until 2.1.6, the server passes a raw request-target containing a backslash in its path to the WHATWG URL parser, which treats the backslash as a path separator and resolves dot segments. A reverse proxy, load balancer, or web application firewall that preserves the backslash and applies path-based rules to the original request can therefore permit a request that the application normalizes to a blocked route. This lets an unauthenticated client reach route content that the upstream component was intended to deny, while Hono application access controls are unaffected because they operate on the normalized path. This issue is fixed in versions 1.19.18 and 2.1.6.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach20/20@hono/node-server: 98M downloads a week
- Severity5.3/10CVSS 5.3
- No patch0/5No signal
What would change the score
- Would score about 87 if added to CISA KEV
- Would score about 82 if CISA's SSVC rates exploitation active
- Would score about 47 if advisories confirm default setups are exposed
Impact
What to do
Upgrade to a fixed version: 2.1.6, 1.19.18.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126210 (@hono/node-server: Backslash in the request path is parsed as a path separator, bypassing path-based access control at a reverse proxy), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-126210 (entry last updated 2026-11-12):
Affected:
- honojs node-server: from 2.0.0, fixed in 2.1.6; fixed in 1.19.18
- npm package @hono/node-server: from 2.0.0, fixed in 2.1.6
- npm package @hono/node-server: fixed in 1.19.18
Fixed versions: 2.1.6, 1.19.18.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-126210 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126210 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Packages (npm): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/honojs/node-server/security/advisories/GHSA-jpvv-r467-5p4w
- https://github.com/honojs/node-server/commit/3868998a805ae79216535ad3986c1e7228dee313
- https://github.com/honojs/node-server/commit/fb97395ec36af66567c76976e741110b02804d1c
- https://github.com/honojs/node-server/releases/tag/v1.19.18
- https://github.com/honojs/node-server/releases/tag/v2.1.6
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-126210
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126210"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- honojs node-server
From 2.0.0 · fixed in 2.1.6; fixed in 1.19.18
From 2.0.0 · fixed in 2.1.6
Fixed in 2.1.6 (released Nov 2, 2026, 10 days before disclosure).
fixed in 1.19.18
Fixed in 1.19.18 (released Nov 2, 2026, 10 days before disclosure).
The latest release, 2.1.6, is not affected.
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 4
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126210
Is CVE-2026-126210 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-126210?
node-server: from 2.0.0 before 2.1.6; before 1.19.18. @hono/node-server (npm): from 2.0.0 before 2.1.6. @hono/node-server (npm): before 1.19.18.Source: cve.now feed data
How do I fix CVE-2026-126210?
Upgrade to a fixed version: 2.1.6, 1.19.18.Source: cve.now feed data