CVE-2026-40898
📛 CVE Title
quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- GitHub_M
- CVSS severity
- MEDIUM
- CVSS score
- 5.3 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Effective score
- 5.3 / 10 MEDIUM source: CNA overview
- CWE(s)
-
CWE-770 - Reserved
- 2026-04-15
- Published
- 2026-06-04 17:43 UTC
- Last updated
- 2026-06-04 18:40 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/40xxx/CVE-2026-40898.json
- Linked Threat
- CVE-2026-40898 — CVE-2026-40898
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-06-04 19:16:28 UTC
- NVD last modified
- 2026-07-22 20:10:00 UTC
- NVD CVSS v3.1
- 5.3 / 10 MEDIUM source: security-advisories@github.com
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Exploitability subscore
- 3.9 / 10
- Impact subscore
- 1.4 / 10
- EPSS score
- 0.0037 (probability of exploitation in next 30 days)
- EPSS percentile
- 29.41% vs all CVEs — higher = more likely to be exploited, as of 2026-07-31
NVD / KEV / EPSS data refreshed 2026-07-31 18:55 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-34312 - Assigner
- GitHub_M
- Published
- Jun 4, 2026, 5:43:36 PM
- Updated
- Jun 4, 2026, 6:40:44 PM
- EUVD base score (CVSS 3.1)
-
5.3 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EUVD-reported EPSS
- 0.3700
- Vendors
- quic-go
- Products
-
quic-go (< 0.59.1)
- Aliases
-
GHSA-vvgj-x9jq-8cj9
ENISA 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.
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| quic-go | quic-go |
< 0.59.1 (affected)
|
— |
Affected products — CPE 2.3 (1) NVD
NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.
cpe:2.3:a:quic-go_project:quic-go:*:*:*:*:*:*:*:*
Vendor references (2)
References embedded in the original CVE record by the assigning CNA.
- https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9 x_refsource_CONFIRM
- https://github.com/quic-go/quic-go/releases/tag/v0.59.1 x_refsource_MISC
Web references (5)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://github.com/quic-go/quic-go/releases/tag/v0.59.1 tenable:github.com
- https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9 tenable:github.com
- https://nvd.nist.gov/vuln/detail/CVE-2026-40898 tenable:nvd.nist.gov
- https://www.cve.org/CVERecord?id=CVE-2026-40898 tenable:www.cve.org
- https://www.first.org/epss/ tenable:www.first.org
NVD-tagged references (2)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://github.com/quic-go/quic-go/releases/tag/v0.59.1 security-advisories@github.com ProductRelease Notes
- https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9 security-advisories@github.com MitigationVendor Advisory
Remediations (19)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:blog.gridinsoft.com
CVE - 2026 -41089 in Windows Netlogon is now reported as actively exploited. Patch domain controllers and check LSASS, Netlogon, and authentication logs.
2026-06-08 15:51 UTC -
web:cvetodo.com
CVE-2026-40898 is a CVSS 5.3 resource exhaustion in quic-go's quic-go. Full technical analysis, mitigations , and exploit status — updated in real time.
2026-06-08 15:51 UTC -
web:cybersecuritynews.com
Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.
2026-06-08 15:51 UTC -
web:mondoo.com
CVE-2026-40898 - MEDIUM severity: quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion
2026-06-08 15:51 UTC -
web:nvd.nist.gov
An official website of the United States government Here's how you know
2026-06-08 15:51 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-06-08 15:51 UTC -
web:techcommunity.microsoft.com
We wanted to tell you how to address the Exchange Server May 2026 vulnerability CVE - 2026 -42897.
2026-06-08 15:51 UTC -
web:vulmon.com
Vulnerability details of CVE-2026-40898 CVE-2026-40898 - Denial of Service via Excessive Memory Allocation in quic-go HTTP/3 Trailers
2026-06-08 15:51 UTC -
web:www.forbes.com
Microsoft has confirmed an emergency security update as CISA warns that two new Defender zero-days are being exploited by attackers.
2026-06-08 15:51 UTC -
web:www.notebookcheck.net
CVE - 2026 -41089, a critical Windows Netlogon flaw rated CVSS 9.8, is now actively exploited. Unpatched domain controllers face full SYSTEM-level compromise with no credentials needed.
2026-06-08 15:51 UTC -
web:cybersecuritynews.com
Microsoft has released its June 2026 Patch Tuesday security updates, addressing a hefty 198 vulnerabilities across its product ecosystem. The June rollout, published on June 9, 2026 , stands out not only for its volume but also for the inclusion of three zero-day vulnerabilities that were actively exploited or publicly known before a fix was available. Administrators are urged to prioritize ...
2026-06-19 02:35 UTC -
web:guide.sonatype.com
Technical security analysis for CVE-2026-40898 . CVSS 7.5 severity. View CVSS vectors, CWE classifications, and exploit maturity ratings.
2026-06-19 02:35 UTC -
web:support.microsoft.com
This update for Windows 11, version 25H2 and 24H2 (KB5084597) incudes security improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates. To view the ...
2026-06-19 02:35 UTC -
web:vulners.com
CVE-2026-40898 affects quic-go (Go QUIC implementation) prior to version 0.59.1. An attacker can cause memory exhaustion by sending a QPACK-encoded HEADERS frame that decodes into a large trailer section with many unique field names or large value...
2026-06-19 02:35 UTC -
web:www.computerworld.com
Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...
2026-06-19 02:35 UTC -
web:www.crowdstrike.com
Microsoft has released security updates for 130 vulnerabilities, including 30 critical, in its May 2026 Patch Tuesday rollout.
2026-06-19 02:35 UTC -
web:www.malwarebytes.com
Microsoft says it's working on a fix for an unpatched Defender vulnerability that can give attackers the highest level of access on Windows.
2026-06-19 02:35 UTC -
web:www.rapid7.com
Microsoft is publishing 200 vulnerabilities on June 2026 Patch Tuesday, including an HTTP/2 denial of service vulnerability and an elevation of privilege vulnerability in PowerToys.
2026-06-19 02:35 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-06-19 02:35 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-40898.json.
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