CVE-2026-59803
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Summary
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| smallnest | rpcx | 0 <= 1.9.3 | affected |
| smallnest | rpcx | 047aec18efa7d037105e2b72c36dd2ae05e1acc6 | unaffected |
Weaknesses
- CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
References
- https://github.com/smallnest/rpcx/issues/942
- https://github.com/smallnest/rpcx/pull/943
- https://github.com/smallnest/rpcx/commit/047aec18efa7d037105e2b72c36dd2ae05e1acc6
- https://www.vulncheck.com/advisories/rpcx-denial-of-service-via-gzip-decompression-bomb-in-wire-protocol
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