CVE-2026-124278
Path bindings ignored for gRPC Content-Types on transcoded routes in elixir-grpc grpc_server
Description
Authorization Bypass Through User-Controlled Key vulnerability in elixir-grpc grpc_server and grpc allows an attacker to make a handler act on a resource other than the one named in the URL of an HTTP-transcoded route, via a request with a gRPC Content-Type. Only the transcoding clause of GRPC.Server.do_handle_request/4 (grpc_server/lib/grpc/server.ex, and lib/grpc/server.ex before the package split) applies the route's path bindings to the request message. The Cowboy handler picks that clause from the request Content-Type, not from the route. A request to a transcoded URL with application/grpc or application/grpc-web is decoded from the body alone, so every path-bound field takes its value from the body. A gateway, proxy rule or WAF that authorizes on the URL path sees one resource while the handler receives another. This issue affects grpc_server: from 1.0.0 before 1.1.0; grpc: from 0.8.0 before 1.0.0.
INFO
Published Date :
Nov. 13, 2026, 4:17 p.m.
Last Modified :
Nov. 13, 2026, 4:17 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Affected Products
The following products are affected by CVE-2026-124278
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update grpc_server to version 1.1.0 or later.
- Update grpc to version 1.0.0 or later.
- Apply security patches for all affected components.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-124278.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-124278 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-124278
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-124278 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-124278 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Nov. 13, 2026
Action Type Old Value New Value Added Description Authorization Bypass Through User-Controlled Key vulnerability in elixir-grpc grpc_server and grpc allows an attacker to make a handler act on a resource other than the one named in the URL of an HTTP-transcoded route, via a request with a gRPC Content-Type. Only the transcoding clause of GRPC.Server.do_handle_request/4 (grpc_server/lib/grpc/server.ex, and lib/grpc/server.ex before the package split) applies the route's path bindings to the request message. The Cowboy handler picks that clause from the request Content-Type, not from the route. A request to a transcoded URL with application/grpc or application/grpc-web is decoded from the body alone, so every path-bound field takes its value from the body. A gateway, proxy rule or WAF that authorizes on the URL path sees one resource while the handler receives another. This issue affects grpc_server: from 1.0.0 before 1.1.0; grpc: from 0.8.0 before 1.0.0. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-436 Added CWE CWE-639 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/124xxx/CVE-2026-124278.json">CVE-2026-124278</a> Added Reference https://cna.erlef.org/cves/CVE-2026-124278.html Added Reference https://github.com/elixir-grpc/grpc/commit/0332faae5f5e132314794dbfdae5edecbccea292 Added Reference https://github.com/elixir-grpc/grpc/commit/8aaf3d3a8c4c7b08ac65e9c6f254e0d24da1d048 Added Reference https://github.com/elixir-grpc/grpc/commit/953ab980d8a127e895d3ab9505fc4b9337bb32f7 Added Reference https://github.com/elixir-grpc/grpc/security/advisories/GHSA-xc5v-89vq-hv5m Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-124278