Vulnerability · Published Jul 8, 2026 · Assigned by VulnCheck

CVE-2026-59803rpcx - Denial of Service via Gzip Decompression Bomb in Wire Protocol

High 7.5

In plain English

A high-severity security flaw in rpcx from smallnest. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.7%top 45.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
smallnest	rpcx	0 – through 1.9.3

Weakness: CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Researcher Disclosure technical-description, exploit
Fix PR issue-tracking
Fix Commit patch
https://www.vulncheck.com/advisories/rpcx-denial-of-service-via-gzip-decompression-bomb-in-wire-protocol third-party-advisory