HTTP/2 server crash due to HPACK encoder race in net/http

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-97032
StatePUBLISHED
AssignerGo
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-08 23:17:06 UTC
Updated2026-10-15 16:18:24 UTC
DescriptionHTTP/2 servers could end up crashing due to inadvertently modifying its HPACK encoder concurrently. This happens because the server modifies the HPACK encoder from two goroutines without synchronization: one uses the encoder to encode a HEADERS frame as part of a response sent to a client and the other modifies the encoder's table size when handling a SETTINGS frame containing SETTINGS_HEADER_TABLE_SIZE that a client sends. A malicious client can repeatedly send a request while changing the header table size to crash the server.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.001810000 probability, percentile 0.070910000 (date 2026-10-11)

Problem Types: CWE-362 | CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') | CWE-362 CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Go Standard Library Net/http affected 1.26.9 semver Not specified
CNA Go Standard Library Net/http/internal/http2 affected 1.27.0-0 1.27.2 semver Not specified
CNA Golang.orgxnet Golang.org/x/net/http2 affected 0.60.0 semver Not specified

References

ReferenceSourceLinkTags
groups.google.com/g/golang-announce/c/ZPwCyRUuGBs [email protected] groups.google.com
groups.google.com/g/golang-announce/c/U2fTuyDJznI [email protected] groups.google.com
go.dev/issue/81867 [email protected] go.dev
go.dev/cl/847188 [email protected] go.dev
pkg.go.dev/vuln/GO-2026-6617 [email protected] pkg.go.dev
go.dev/cl/847313 [email protected] go.dev
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: RyotaK (https://ryotak.net) of GMO Flatt Security Inc. (en)

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