What is CVE-2026-59803?

CVE-2026-59803 is a high-severity vulnerability in Smallnest Rpcx, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-07-08.

How severe is CVE-2026-59803?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Smallnest Rpcx

CVE-2026-59803

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…

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Smallnest Rpcx — versions 0, 047aec18efa7d037105e2b72c36dd2ae05e1acc6

Weakness classification (CWE)

CWE-409 — Improper Handling of Highly Compressed Data (Data Amplification)

References

disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-59803?: CVE-2026-59803 is a high-severity vulnerability in Smallnest Rpcx, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-07-08.
How severe is CVE-2026-59803?: High severity. CVSS v3 base score is 7.5 out of 10.