# CVE-2026-31812: Quinn quinn-proto denial of service via malformed QUIC packet

Source: https://junglewise.ai/threats/cve-2026-31812-quinn-quinn-proto-denial-of-service-via-malformed-quic-packet  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-10. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2026-31812 · Severity: medium · CVSS 5.3 · Published 2026-03-10

Quinn is a software library used by applications to communicate using the QUIC internet protocol. A remote attacker can send a single specially crafted data packet to a server using this library, causing the application to crash immediately. This results in a denial of service, potentially disrupting business operations and service availability for customers without requiring any login credentials.

Technologies: [quinn-proto (crates.io)](https://junglewise.ai/threats/technologies/crates-io-quinn-proto), [Quinn-Rs Quinn-Proto](https://junglewise.ai/threats/technologies/quinn-proto). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io), [Quinn-Rs](https://junglewise.ai/threats/vendors/quinn-rs).

## Quick answers

**Is CVE-2026-31812 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-31812 being exploited in the wild.

**How severe is CVE-2026-31812?** Medium severity, with a CVSS score of 5.3, published 10 March 2026.

**Which products and versions are affected?** quinn-proto (crates.io) SEMVER:introduced=0,fixed=0.11.14, SEMVER:introduced=0.5.0,fixed=0.11.14; Quinn-Rs Quinn-Proto < 0.11.14.

**Is there a fix for CVE-2026-31812?** Yes. quinn-proto (crates.io): upgrade to 0.11.14 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-31812 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-31812?** Check whether you run quinn-proto (crates.io) or Quinn-Rs Quinn-Proto at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- quinn-proto (crates.io): upgrade to 0.11.14 or later

  ```sh
  cargo update -p quinn-proto
  ```


## Technical details

A denial of service vulnerability exists in quinn-proto due to an uncaught exception (panic) during the parsing of QUIC transport parameters. The root cause is the use of the `unwrap()` method on a fallible varint decoding operation; when a truncated or malformed varint is encountered, the decoder returns an `UnexpectedEnd` error, which triggers a thread panic. An unauthenticated remote attacker can exploit this by sending a single crafted QUIC Initial packet containing malformed `quic_transport_parameters`. The vulnerability is fixed in version 0.11.14 of the Quinn library.

## Affected products

- quinn-rs quinn-proto < 0.11.14
- Red Hat Red Hat Ansible Automation Platform 2.6
- Red Hat Red Hat OpenShift Container Platform 4
- Red Hat Red Hat Enterprise Linux 9, 10

## Identifiers

- CVE-2026-31812
- GHSA-6xvm-j4wr-6v98
- RUSTSEC-2026-0037

## Timeline

- 2026-03-09: advisory: GitHub Security Advisory GHSA-6xvm-j4wr-6v98 published
- 2026-03-10: disclosed: CVE-2026-31812 published to NVD
- 2026-05-04: patched: Red Hat released security updates for Ansible Automation Platform

## References

- [https://github.com/quinn-rs/quinn/security/advisories/GHSA-6xvm-j4wr-6v98](https://github.com/quinn-rs/quinn/security/advisories/GHSA-6xvm-j4wr-6v98)
- [https://access.redhat.com/errata/RHSA-2026:13545](https://access.redhat.com/errata/RHSA-2026:13545)
- [https://access.redhat.com/errata/RHSA-2026:19712](https://access.redhat.com/errata/RHSA-2026:19712)
- [https://access.redhat.com/errata/RHSA-2026:22862](https://access.redhat.com/errata/RHSA-2026:22862)
- [https://access.redhat.com/errata/RHSA-2026:5459](https://access.redhat.com/errata/RHSA-2026:5459)
- [https://access.redhat.com/security/cve/CVE-2026-31812](https://access.redhat.com/security/cve/CVE-2026-31812)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2446330](https://bugzilla.redhat.com/show_bug.cgi?id=2446330)

## Related threats

- [RUSTSEC-2026-0343 - Outgoing datagram buffer accounting can panic the sender in quinn-proto](https://junglewise.ai/threats/rustsec-2026-0343-outgoing-datagram-buffer-accounting-can-panic-the-270f6598)
- [RUSTSEC-2026-0340 - Peer minimum ACK delay can panic quinn-proto when ACK_FREQUENCY transmission is enabled](https://junglewise.ai/threats/rustsec-2026-0340-peer-minimum-ack-delay-can-panic-quinn-proto-when-ack-29882a7a)
- [quinn-proto denial of service in unordered stream reads](https://junglewise.ai/threats/rustsec-2026-0338-remote-peer-can-panic-quinn-proto-with-zero-length-c5ff03b1)
- [RUSTSEC-2026-0339 - Unbounded growth of pending connection ID retirements in quinn-proto](https://junglewise.ai/threats/rustsec-2026-0339-unbounded-growth-of-pending-connection-id-retirements-0568d867)
- [RUSTSEC-2026-0342 - Zero-length DATAGRAM frames bypass the receive buffer limit in quinn-proto](https://junglewise.ai/threats/rustsec-2026-0342-zero-length-datagram-frames-bypass-the-receive-buffer-613ca2dc)