smallnest rpcx up to 1.9.3 Message Decode protocol/message.go Message.Decode allocation of resources

Summaryinfo

A vulnerability categorized as problematic has been discovered in smallnest rpcx up to 1.9.3. This affects the function Message.Decode of the file protocol/message.go of the component Message Decode. Executing a manipulation can lead to allocation of resources. This vulnerability is tracked as CVE-2026-59803. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in smallnest rpcx up to 1.9.3. It has been declared as problematic. This vulnerability affects the function Message.Decode of the file protocol/message.go of the component Message Decode. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. CVE summarizes:

rpcx through 1.9.3, fixed in commit 047aec1, contains a denial-of-service vulnerability in protocol.Message.Decode (protocol/message.go). When a message has the compression flag set, the payload is gzip-decompressed via util.Unzip with no limit on the decompressed output size. The only built-in size guard, protocol.MaxMessageLength, is checked against the compressed on-the-wire frame length, not the decompressed size, so it provides no protection. Because decoding (and decompression) occurs in readRequest before authentication, a single unauthenticated connection can send a small (under 2 MB) gzip-compressed message that expands to gigabytes of heap allocation, leading to out-of-memory conditions and service unavailability.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-59803 since 07/07/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• smallnest

Name

• rpcx

Version

• 1.9.0
• 1.9.1
• 1.9.2
• 1.9.3

Website

• Product: https://github.com/smallnest/rpcx/

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