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.

High
CVSS
7.5
important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0040
34th percentile

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

ProductFixed inFixReleased
Linux
govulncheck-vulndb · opensuse-leap 16.0 0.0.20260723T184607-160000.1.1 OPENSUSE-SU-2026:21483-1 Jul 30, 2026
prometheus · Fedora 43 3.13.1-1.fc43 FEDORA-2026-6A44DB4FA9 Jul 11, 2026
prometheus-debuginfo · Fedora 43 3.13.1-1.fc43 FEDORA-2026-6A44DB4FA9 Jul 11, 2026
prometheus-debugsource · Fedora 43 3.13.1-1.fc43 FEDORA-2026-6A44DB4FA9 Jul 11, 2026
receptor · RHEL 10 1.6.7-1.el10ap RHSA-2026:50318 Jun 4, 2026

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