CVE-2026-27690: @sap/approuter SAP Approuter Vulnerable To HTTP Vulnerability

CRITICAL
Advisory Identifier: GHSA-8m85-wqg7-c529
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CVSS 9.1
CWE-444
Published
Advisory Summary

CVE-2026-27690 is a CRITICAL (CVSS 9.1) sap approuter vulnerable to http vulnerability (CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) affecting @sap/approuter libraries in the npm ecosystem. The issue involves sap approuter vulnerable to http request smuggling. Remediation is available by upgrading affected packages to version 20.10.0.

CVE-2026-27690 at a Glance

CVE Identifier CVE-2026-27690
GHSA Identifier GHSA-8m85-wqg7-c529
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Product @sap/approuter
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-27690

To remediate this vulnerability, upgrade all affected @sap/approuter dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@sap/approuter fixed: 20.10.0 
npm install @sap/approuter@20.10.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @sap/approuter

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-27690, inspect your project dependencies using npm:

npm ls @sap/approuter

Analyze the terminal output to locate any version of @sap/approuter in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 20.10.0), your application is affected.

Note: The npm ls @sap/approuter command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), where the product acts as an intermediary http agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed http requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. In @sap/approuter, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Due to an HTTP Request Smuggling vulnerability in SAP Approuter, an unauthenticated attacker could send a specially crafted HTTP request that leads to request-response desynchronization. This could result in the exposure of user responses and cause the system to become unavailable. This leads to a high impact on confidentiality and availability.

CVE-2026-27690 Affected @sap/approuter Versions

1 component(s)
Fixed Versions:
20.10.0
Product / Package Ecosystem Affected Versions Fixed Version
@sap/approuter
npm/@sap/approuter
npm
< 20.10.0
20.10.0

References

NVD — CVE-2026-27690 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27690
me.sap.com/notes/3720138 WEB
https://me.sap.com/notes/3720138
@sap/approuter Security Information SECURITY
https://url.sap/sapsecuritypatchday

Frequently Asked Questions

What is CVE-2026-27690?
CVE-2026-27690 is a security vulnerability in @sap/approuter involving SAP Approuter Vulnerable to HTTP Request Smuggling under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').
Which @sap/approuter versions are affected?
Affected versions include releases prior to 20.10.0 across affected packages: @sap/approuter.
What version fixes CVE-2026-27690?
Upgrading to 20.10.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @sap/approuter affected?
Yes, @sap/approuter is affected in releases prior to 20.10.0. Upgrade your dependency to 20.10.0 or later.
What is the CVSS score of CVE-2026-27690?
CVE-2026-27690 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
What CWE is associated with CVE-2026-27690?
CVE-2026-27690 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).
How can I check npm dependencies for CVE-2026-27690?
Run the dependency tree command: 'npm ls @sap/approuter'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8m85-wqg7-c529",
  "modified" : "2026-09-01T21:20:31Z",
  "published" : "2026-07-14T03:31:35Z",
  "aliases" : [ "CVE-2026-27690" ],
  "summary" : "SAP Approuter Vulnerable to HTTP Request Smuggling",
  "details" : "Due to an HTTP Request Smuggling vulnerability in SAP Approuter, an unauthenticated attacker could send a specially crafted HTTP request that leads to request-response desynchronization. This could result in the exposure of user responses and cause the system to become unavailable. This leads to a high impact on confidentiality and availability.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@sap/approuter"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "20.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27690"
  }, {
    "type" : "WEB",
    "url" : "https://me.sap.com/notes/3720138"
  }, {
    "type" : "WEB",
    "url" : "https://url.sap/sapsecuritypatchday"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-01T21:20:31Z",
    "nvd_published_at" : "2026-07-14T01:16:17Z"
  }
}