A data race in the RDMA transport of Apache bRPC (versions < 1.18.0) allows a remote client to crash the server process (denial of service) when RDMA is enabled at build time and runtime.
Root Cause:
When a bRPC server negotiates RDMA with a client, the handshake completes on the TCP fd, but the server kept parsing that fd afterwards as if it were still an RPC channel. The TCP-fd input stream and the RDMA QP input stream (driven by CQ events) shared the same Socket::_read_buf, preferred_index and parsing_context without synchronization. In addition, CQ event processing could start while the handshake parsing was still in progress, and the handshake ACK phase could consume bytes belonging to the next protocol. A remote, unauthenticated client that has completed the RDMA handshake can send data on the TCP fd at the same time RDMA messages are being processed, corrupting the shared input buffer and parser state and crashing the server process (CWE-362, availability impact).
Affected Scenarios:
Use a bRPC server with RDMA support enabled (built with BRPC_WITH_RDMA and serving rdma:// / SOCKET_MODE_RDMA sockets) and accept connections from untrusted clients. Deployments without RDMA are not affected.
How to Fix:
(Choose one of the following options)
- Upgrade bRPC to version 1.18.0, which fixes this issue.
- Apply this patch: https://github.com/apache/brpc/pull/3505
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- EG Likelihood
- 0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the BOD 26-04 block below.
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it