---
id: CVE-2026-31812
title: >-
  Quinn is a pure-Rust, async-compatible implementation of the IETF QUIC
  transport protocol
summary: >-
  Quinn is a pure-Rust, async-compatible implementation of the IETF QUIC
  transport protocol. Prior to 0.11.14, a remote, unauthenticated attacker can
  trigger a denial of service in applications using vulnerable quinn versions by
  sending a …
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-248
  - CWE-248
published: '2026-03-10'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31812'
references:
  - url: 'https://github.com/quinn-rs/quinn/security/advisories/GHSA-6xvm-j4wr-6v98'
    label: security-advisories@github.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:13545'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19712'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:22862'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:5459'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-31812'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2446330'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31812.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00889
epssPercentile: 0.57648
ingestedAt: '2026-07-27T13:18:48.140Z'
---

## Overview

Quinn is a pure-Rust, async-compatible implementation of the IETF QUIC transport protocol. Prior to 0.11.14, a remote, unauthenticated attacker can trigger a denial of service in applications using vulnerable quinn versions by sending a crafted QUIC Initial packet containing malformed quic_transport_parameters. In quinn-proto parsing logic, attacker-controlled varints are decoded with unwrap(), so truncated encodings cause Err(UnexpectedEnd) and panic. This is reachable over the network with a single packet and no prior trust or authentication. This vulnerability is fixed in 0.11.14.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.