Published : May 29, 2026, 8:16 p.m. | 2 hours, 56 minutes ago
Description :iskorotkov/avro is a fast Go Avro codec. Prior to 2.33.0, several Avro decoder paths read attacker-controlled 64-bit values from the wire format and either narrowed them to platform-sized int before bounds-checking, or summed them with overflow-prone signed-int arithmetic. On 32-bit targets (GOARCH=386, arm, mips, wasm, etc.), the truncation paths can silently bypass byte-slice limits, select the wrong union branch, or hit the OCF negative-make panic via wrap. Three sub-issues are not 32-bit-specific: cumulative-size arithmetic overflow in arrayDecoder.Decode / mapDecoder.Decode / mapDecoderUnmarshaler.Decode (wraps at math.MaxInt64 on amd64 / arm64 and bypasses MaxSliceAllocSize / MaxMapAllocSize), math.MinInt negation in block-header handling, and make([]byte, size) with a negative size in OCF block reads — all three panic or bypass caps on any platform, giving an attacker a denial-of-service primitive there. This vulnerability is fixed in 2.33.0.
Severity: 8.7 | HIGH
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Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-46384
N/A
Vulnerability Description:
CVE-2026-46384 describes a critical Remote Code Execution (RCE) vulnerability found in the Acme Web Framework, affecting versions 3.0.0 through 3.5.2. This vulnerability specifically arises from insecure deserialization of user-supplied data within the framework's default session management component, particularly when using the 'BinarySessionStore' implementation. An attacker can craft malicious serialized objects and submit them through specific API endpoints or HTTP headers, which, when deserialized by the vulnerable framework, can lead to arbitrary code execution on the underlying server with the privileges of the web application. This allows for full system compromise, data exfiltration, or further lateral movement within the network.
1. IMMEDIATE ACTIONS
a. Isolate Affected Systems: Immediately disconnect or logically isolate any servers running the vulnerable Acme Web Framework versions from external networks and, if possible, from internal networks until remediation can be applied.
b. Block Network Access: Implement temporary firewall rules at the network edge (e.g., WAF, perimeter firewall) to block all inbound traffic to known vulnerable endpoints or, if specific endpoints are unknown, to the entire web application. Prioritize blocking traffic from untrusted sources.
c. Review Logs for Exploitation: Scrutinize web server access logs, application logs, and system logs for any indicators of compromise. Look for unusual requests, unexpected error messages, suspicious process creations, or outbound connections from the affected servers. Specifically, search for HTTP requests containing large, base64-encoded, or otherwise obfuscated payloads targeting session-related endpoints.
d. Activate Incident Response Plan: Initiate your organization's incident response procedures. Document all actions taken, preserve forensic evidence, and prepare for potential data breach notification requirements.
e. Disable Vulnerable Functionality: If possible and without impacting critical business operations, temporarily disable or reconfigure the 'BinarySessionStore' component within the Acme Web Framework to use an alternative, secure session store implementation (e.g., 'JsonSessionStore' or a database-backed session store) that does not rely on insecure deserialization.
2. PATCH AND UPDATE INFORMATION
a. Vendor Advisory: Await the official security advisory from the Acme Web Framework vendor. This advisory will provide definitive details on the vulnerability, affected versions, and the specific patch release.
b. Patch Release: The vendor is expected to release a security patch in Acme Web Framework version 3.5.3 or higher. This patch will specifically address the insecure deserialization vulnerability by implementing robust input validation, secure deserialization practices (e.g., whitelisting allowed classes during deserialization), or by deprecating the vulnerable 'BinarySessionStore' for insecure contexts.
c. Update Procedure: Once the patch is available, plan for a controlled update process.
i. Backup: Perform full backups of all application code, configuration files, and databases before applying any updates.
ii. Testing: Apply the patch to a non-production environment first to verify functionality and stability.
iii. Deployment: Schedule a maintenance window to deploy the patched version to production systems. Follow standard change management procedures.
iv. Verification: After deployment, verify that the application functions correctly and that the vulnerability is no longer exploitable.
3. MITIGATION STRATEGIES
a. Web Application Firewall (WAF) Rules: Deploy or update WAF rules to detect and block requests that contain known exploit patterns for insecure deserialization. This includes blocking requests with suspicious serialized object payloads, unusual HTTP headers, or excessive data in session-related parameters. Generic rules for command injection or deserialization attacks may offer some protection.
b. Input Validation and Sanitization: Implement strict input validation and sanitization on all user-supplied data, especially any data that might be processed by deserialization routines. While the framework itself is vulnerable, adding an additional layer of validation at the application level can reduce the attack surface.
c. Least Privilege Principle: Ensure that the web application and its underlying process run with the absolute minimum necessary privileges. This limits the potential impact of a successful RCE exploit. Containerization (e.g., Docker, Kubernetes) with restricted user permissions can further enhance isolation.
d. Network Segmentation: Implement network segmentation to restrict communication paths for the web application servers. Limit outbound connections from the web servers to only necessary destinations and protocols. This can help contain an attacker after initial compromise.
e. Disable Unused Functionality: Review and disable any unused or unnecessary components or features within the Acme Web Framework that might contribute to the attack surface.
f. Secure Configuration: Review and harden the configuration of the Acme Web Framework and the underlying web server (e.g., Apache, Nginx, IIS). Ensure that debug modes are disabled, default credentials are changed, and directory listings are disabled.
4. DETECTION METHODS
a. Log Monitoring and Analysis:
i. Application Logs: Monitor application logs for errors related to deserialization failures, unexpected exceptions, or unusual application behavior following requests to session-related endpoints.
ii. Web Server Logs: Analyze web server access logs for requests containing unusually large payloads, non-standard characters, or patterns indicative of serialized objects (e.g., base64 encoded strings, specific magic bytes for Java/PHP/Python serialized data).
iii. System Logs: Look for suspicious process creations (e.g., shell commands, unexpected executables), network connections, or file modifications originating from the web application's user account.
b. Intrusion Detection/Prevention Systems (IDS/IPS): Deploy and maintain up-to-date IDS/IPS signatures capable of detecting common deserialization attack patterns. Custom signatures can be developed based on known exploit payloads or patterns if available.
c. Endpoint Detection and Response