CVE-2026-55428
Coder: Route hijacking through lack of validation of agent-supplied AllowedIPs in tailnet coordinator
Description
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the tailnet coordinator validates that an agent's `Addresses` derive from its authenticated UUID but applies no equivalent check to `AllowedIPs`. The coordinator forwards agent-supplied `AllowedIPs` verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each `AllowedIPs` prefix against the authenticating agent's UUID just like `Addresses`. As a workaround, monitor coordinator logs for agents advertising unexpected `AllowedIPs` prefixes.
INFO
Published Date :
July 8, 2026, 12:16 a.m.
Last Modified :
July 8, 2026, 7:44 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update Coder to versions 2.29.7 or later.
- Update Coder to versions 2.32.7 or later.
- Update Coder to versions 2.33.8 or later.
- Update Coder to versions 2.34.2 or later.
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-2026-55428.
| URL | Resource |
|---|---|
| https://github.com/coder/coder/pull/26144 | Issue Tracking Patch |
| https://github.com/coder/coder/releases/tag/v2.29.17 | Release Notes |
| https://github.com/coder/coder/releases/tag/v2.32.7 | Release Notes |
| https://github.com/coder/coder/releases/tag/v2.33.8 | Release Notes |
| https://github.com/coder/coder/releases/tag/v2.34.2 | Release Notes |
| https://github.com/coder/coder/security/advisories/GHSA-wrq8-fcv5-8hvp | Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55428 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-2026-55428
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-2026-55428 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55428 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.
-
Initial Analysis by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:* versions up to (excluding) 2.29.17 *cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:* versions from (including) 2.30.0 up to (excluding) 2.32.7 *cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:* versions from (including) 2.33.0 up to (excluding) 2.33.8 *cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:* versions from (including) 2.34.0 up to (excluding) 2.34.2 Added Reference Type GitHub, Inc.: https://github.com/coder/coder/pull/26144 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/coder/coder/releases/tag/v2.29.17 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/coder/coder/releases/tag/v2.32.7 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/coder/coder/releases/tag/v2.33.8 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/coder/coder/releases/tag/v2.34.2 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/coder/coder/security/advisories/GHSA-wrq8-fcv5-8hvp Types: Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 08, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-55428', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-08T13:10:59.507766Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'coder', 'product': 'coder', 'versions': [{'status': 'affected', 'version': '>= 2.34.0, < 2.34.2'}, {'status': 'affected', 'version': '>= 2.33.0, < 2.33.8'}, {'status': 'affected', 'version': '>= 2.30.0, < 2.32.7'}, {'status': 'affected', 'version': '< 2.29.17'}]}] Added Description Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the tailnet coordinator validates that an agent's `Addresses` derive from its authenticated UUID but applies no equivalent check to `AllowedIPs`. The coordinator forwards agent-supplied `AllowedIPs` verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each `AllowedIPs` prefix against the authenticating agent's UUID just like `Addresses`. As a workaround, monitor coordinator logs for agents advertising unexpected `AllowedIPs` prefixes. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N Added CWE CWE-285 Added CWE CWE-863 Added Reference https://github.com/coder/coder/pull/26144 Added Reference https://github.com/coder/coder/releases/tag/v2.29.17 Added Reference https://github.com/coder/coder/releases/tag/v2.32.7 Added Reference https://github.com/coder/coder/releases/tag/v2.33.8 Added Reference https://github.com/coder/coder/releases/tag/v2.34.2 Added Reference https://github.com/coder/coder/security/advisories/GHSA-wrq8-fcv5-8hvp