A reachable assertion in Apache bRPC (version < 1.18.0) on all platforms allows a malicious remote peer to crash the process, resulting in denial of service.
Root Cause:
When a Socket with health checking enabled fails, Socket::WaitAndReset closes its file descriptor while the event dispatcher may still be delivering an input event (EPOLLIN/EVFILT_READ) that was fetched for the just-closed fd. If the health check then succeeds and revives the Socket, Socket::Address succeeds again while the fd is still -1 (the next write reconnects on demand). In that window, Socket::OnInputEvent hits CHECK(!(events & EPOLLIN)) (or the kqueue equivalent) because the Socket is addressable but has no fd. CHECK failures terminate the process when bRPC is built with glog or when the gflag -crash_on_fatal_log is enabled (CHECK always terminates in OFFICIAL_BUILD/NDEBUG builds as well).
Affected Scenarios:
Applications using bRPC clients with health check enabled (-health_check_interval). A malicious remote peer that the client connects to can deliberately abort connections and immediately accept the health check probes, racing connection teardown against health check revival to trigger the assertion and abort the process.
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/3510
Note:
After applying the fix, stale input events on a Socket revived without an fd are silently dropped instead of triggering the assertion. No user-visible interface or wire protocol is changed.
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