# CVE-2026-40898: receptor: quic-go is an implementation of the QUIC protocol in Go

CVE-2026-40898 is fixed in 5 products on 1 platform, first by RHSA-2026:50318, released June 4, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-40898
- Priority: High
- CVSS: 7.5 (important)
- EPSS: 0.0040
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 4, 2026

## Description

quic-go is an implementation of the QUIC protocol in Go. Prior to version 0.59.1, an attacker can cause excessive memory allocation in quic-go's HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large trailer field section with many unique field names and/or large values. The implementation builds an `http.Header` for the corresponding `http.Request` or `http.Response`, while only enforcing limits on the size of the QPACK-compressed HEADERS frame, not on the decoded field section. This can lead to memory exhaustion. This is very similar to CVE-2025-64702. The difference is that this issue uses HTTP trailers, rather than HTTP headers, as the attack vector. A misbehaving or malicious peer can cause a denial-of-service (DoS) attack against quic-go's HTTP/3 servers or clients by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. This affects both servers and clients due to symmetric header construction. Version 0.59.1 enforces RFC 9114 decoded field section size limits for trailers as well. It incrementally decodes QPACK entries and checks the field section size after each entry, aborting the stream if an entry causes the limit to be exceeded.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | [OPENSUSE-SU-2026:21483-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21483-1.md) | Jul 30, 2026 |
| Linux | prometheus Fedora 43 | 3.13.1-1.fc43 | [FEDORA-2026-6A44DB4FA9](https://patchblox.com/security/data/fix/linux/fedora-2026-6a44db4fa9.md) | Jul 11, 2026 |
| Linux | prometheus-debuginfo Fedora 43 | 3.13.1-1.fc43 | [FEDORA-2026-6A44DB4FA9](https://patchblox.com/security/data/fix/linux/fedora-2026-6a44db4fa9.md) | Jul 11, 2026 |
| Linux | prometheus-debugsource Fedora 43 | 3.13.1-1.fc43 | [FEDORA-2026-6A44DB4FA9](https://patchblox.com/security/data/fix/linux/fedora-2026-6a44db4fa9.md) | Jul 11, 2026 |
| Linux | receptor RHEL 10 | 1.6.7-1.el10ap | [RHSA-2026:50318](https://patchblox.com/security/data/fix/linux/rhsa-2026-50318.md) | Jun 4, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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