CVE-2026-90484 Apache bRPC: Null pointer dereference in MySQL reply parser leading to client crash
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-90484?
CVE-2026-90484 is a medium-severity vulnerability in Apache bRPC, published on 21 Oct 2026.
Official description
The MySQL client response parser in Apache bRPC dereferences a null pointer when the server peer sends a zero-payload-length response packet. A response packet whose declared payload length is zero is accepted by the frame-length check (is_full_package), after which the parser reads the response type byte via an unbounded 5-byte fetch that returns nullptr, and type = p[4] dereferences it, crashing the client process.
Root Cause: In brpc::policy::MysqlReply::ConsumePartialIOBuf, buf.fetch(header, 5) returns nullptr when the buffered data only holds the 4-byte header of a zero-length packet, then the code reads p[4] (and, in the fast-auth path, p2[4]) without checking for a null or zero-length packet.
Affected Scenarios: A brpc MySQL client connecting to a malicious or compromised MySQL server (or a MITM) can be crashed by a zero-length server response packet, resulting in denial of service of the client.
Fix: The fix rejects zero-length response packets (returning PARSE_ERROR_ABSOLUTELY_WRONG) both for the initial response type determination and after a fast-auth marker, before reading the type byte. Upgrade to the Apache bRPC version 1.18.0 or apply the PR patch at https://github.com/apache/brpc/pull/3536.
Weakness: CWE-476
Which versions are affected by CVE-2026-90484?
How do I fix CVE-2026-90484?
No fix has been published for CVE-2026-90484 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-90484 being exploited?
There is no known exploitation of CVE-2026-90484 in the wild and no public exploit code.
Sources
Also known as GHSA-rf6j-677g-5547.