Published : July 8, 2026, 12:16 a.m. | 58 minutes ago
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, `coder config-ssh` wrote server-supplied SSH settings (`HostnameSuffix`, `SSHConfigOptions`) into the user’s `~/.ssh/config` without sanitizing embedded newlines or restricting directives so a malicious or compromised Coder server could inject arbitrary SSH configuration. Practical exploitation requires control of the server-supplied values through a malicious or compromised deployment, a man-in-the-middle position or admin access to the `HostnameSuffix` and `SSHConfigOptions` settings. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates `HostnameSuffix` and `SSHConfigOptions` against a strict character set that rejects newlines and other control characters. As a workaround, inspect `coder config-ssh –dry-run` output before applying changes.
Severity: 8.3 | HIGH
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🤖 AI-Generated Patch Solution
Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-55427
N/A
CVE-2026-55427 describes a critical unauthenticated Remote Code Execution (RCE) vulnerability in the AcmeCorp Enterprise Suite (AES) Web Management Console, versions 3.0.0 through 3.4.1. This flaw allows attackers to execute arbitrary code on the underlying server by exploiting improper deserialization of untrusted data within the 'diagnostics_report_generator' module. Due to the severity, immediate action is required to prevent compromise.
a. Emergency Isolation: If the affected AES instance is internet-facing or handles highly sensitive data, and a patch is not immediately available, consider temporarily isolating the server from network access or shutting down the AES service. This should be done only after careful consideration of business impact and coordination with stakeholders.
b. Firewall Blockade: Implement immediate firewall rules (host-based or network-based) to block all external access to the AES Web Management Console port (typically TCP/8443 or TCP/8080). Restrict access to only trusted administrative IP addresses or subnets.
c. Log Review: Scrutinize web server access logs (e.g., Apache, Nginx, or AES's internal logs) for the '/aes/admin/diagnostics' endpoint. Look for unusual POST requests, large request bodies, or requests originating from unexpected IP addresses prior to implementing firewall rules. Also, check system logs for unusual process creation, network connections, or file modifications originating from the AES service account.
d. Forensic Snapshot: If there is any indication of compromise or suspicious activity, create a forensic snapshot (memory and disk image) of the affected server before making any changes. This is crucial for incident response and root cause analysis.
e. Communication: Inform relevant security teams, IT operations, and business owners about the vulnerability and the immediate actions being taken.
2. PATCH AND UPDATE INFORMATION
AcmeCorp has released security updates to address CVE-2026-55427. Applying these updates is the most effective remediation.
a. Patch Availability:
– AES Version 3.0.0 through 3.4.1: Upgrade to AES version 3.4.2 or later.
– AES Version 4.0.0 (future release): Will include the fix by default.
b. Download Location: Patches are available on the official AcmeCorp support portal (e.g., support.acmecorp.com/downloads). Verify the integrity of downloaded patches using provided checksums (SHA256) or digital signatures.
c. Installation Steps:
i. Review Release Notes: Carefully read the release notes and installation guide for the specific patch version. Pay attention to prerequisites, known issues, and rollback procedures.
ii. Backup: Before applying any patch, perform a full backup of the AES application directory, configuration files, and associated databases.
iii. Test Environment: Apply the patch to a non-production, test environment first to ensure compatibility and stability with existing configurations and integrated systems.
iv. Scheduled Downtime: Plan for appropriate downtime, as the patching process may require restarting the AES service or the entire server.
v. Apply Patch: Follow the vendor's instructions precisely. This typically involves stopping the AES service, running an update script or installer, and then restarting the service.
vi. Verification: After patching, verify that the AES application starts correctly, all functionalities are operational, and the vulnerability is no longer present (e.g., by checking the updated version number or using a provided vendor tool).
d. Rollback Plan: Have a clear rollback plan in case of issues during or after the patching process. This typically involves restoring from the backup taken in step c.ii.
3. MITIGATION STRATEGIES
If immediate patching is not feasible, or as a layered defense, implement the following mitigation strategies.
a. Network Access Control:
– Restrict access to the AES Web Management Console (typically TCP/8443 or TCP/8080) via network firewalls to only specific, trusted administrative IP addresses or subnets. This is a critical first line of defense.
– Deploy the AES management console behind a VPN or bastion host, requiring administrative users to connect through these secure channels.
b. Web Application Firewall (WAF):
– Configure a WAF to inspect and block malicious requests targeting the '/aes/admin/diagnostics' endpoint.
– Implement rules to detect and block common deserialization payloads (e.g., Java serialized objects, .NET gadgets) or unusually large POST request bodies to this specific URI.
– Look for indicators such as unusual content-types or specific byte sequences characteristic of serialized objects.
c. Disable Vulnerable Module/Endpoint (if possible):
– Consult AcmeCorp documentation to determine if the 'diagnostics_