CVE-2026-40898

Aliases:GHSA-vvgj-x9jq-8cj9GO-2026-5676
Advisory lineage Upstream: 0 Downstream: 4
Analyzed
Published: 04 Jun 2026, 17:43
Last modified:04 Jun 2026, 18:40

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (nvd)
EPSS Score
0.28% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

04 Jun 2026, 17:43
Published
Vulnerability first disclosed
04 Jun 2026, 18:40
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.28%• Percentile: 20%

Techniques & Countermeasures

  • CWE-770•Allocation of Resources Without Limits or Throttling

    The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Affected Systems

  • github.com/quic-go•quic-go

    < 0.59.1

  • quic-go_project•quic-go

    < 0.59.1

  • quic-go•quic-go

    < 0.59.1

References (7)