---
id: CVE-2026-78667
title: >-
  When parsing a Range header containing a large number of small ranges,
  FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive
  amount of CPU.
summary: >-
  When parsing a Range header containing a large number of small ranges,
  FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive
  amount of CPU.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: stdlib
product: stdlib
affected:
  - 'stdlib >= 1.27.0-0, < 1.27.2'
patched:
  - stdlib 1.27.2
published: '2026-10-08'
updated: '2026-10-09'
sourceUpdated: '2026-10-09T17:16:49.690'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78667'
references:
  - url: 'https://go.dev/cl/847309'
    label: security@golang.org
  - url: 'https://go.dev/issue/81858'
    label: security@golang.org
  - url: 'https://groups.google.com/g/golang-announce/c/U2fTuyDJznI'
    label: security@golang.org
  - url: 'https://pkg.go.dev/vuln/GO-2026-6609'
    label: security@golang.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-78667.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-78667'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2548334'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-78667'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78667'
  - url: 'https://access.redhat.com/errata/RHSA-2026:86093'
  - url: 'https://access.redhat.com/errata/RHSA-2026:86203'
  - url: 'https://access.redhat.com/errata/RHSA-2026:86196'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87040'
  - url: 'https://access.redhat.com/errata/RHSA-2026:88262'
  - url: 'https://access.redhat.com/errata/RHSA-2026:88280'
  - url: 'https://access.redhat.com/errata/RHSA-2026:88336'
  - url: 'https://access.redhat.com/errata/RHSA-2026:88188'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87246'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87041'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87042'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87043'
  - url: 'https://access.redhat.com/errata/RHSA-2026:87245'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89884'
  - url: 'https://access.redhat.com/errata/RHSA-2026:88397'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89892'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89751'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89752'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89832'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89761'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89760'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89741'
  - url: 'https://access.redhat.com/errata/RHSA-2026:89888'
tags:
  - nvd
  - osv
  - go
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.0048
epssPercentile: 0.41244
aliases:
  - GO-2026-6609
  - BIT-golang-2026-78667
ecosystem: go
ingestedAt: '2026-10-09T00:19:50.976Z'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-09T16:12:49.383383Z'
---

## Overview

When parsing a Range header containing a large number of small ranges, FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive amount of CPU.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-78667)

Affected packages:

- `stdlib >= 1.27.0-0, < 1.27.2`

Patched in:

- `stdlib 1.27.2`

Source: https://osv.dev/vulnerability/GO-2026-6609

## Vendor advisories

- **Red Hat VEX** · Important · affected: OpenShift Developer Tools and Services, OpenShift Pipelines, OpenShift Serverless, OpenShift Service Mesh 3, Red Hat Ansible Automation Platform 2, Red Hat Ceph Storage 7, … · no fix planned: OpenShift Developer Tools and Services, OpenShift Pipelines, OpenShift Serverless, OpenShift Service Mesh 3, … · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-78667.json)
- **RHSA-2026:86093** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:86093)
- **RHSA-2026:86203** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8) · released 2026-10-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:86203)
- **RHSA-2026:86196** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-10-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:86196)
- **RHSA-2026:87040** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87040)
- **RHSA-2026:88262** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88262)
- **RHSA-2026:88280** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88280)
- **RHSA-2026:88336** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88336)
- **RHSA-2026:88188** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8) · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88188)
- **RHSA-2026:87246** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87246)
- **RHSA-2026:87041** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87041)
- **RHSA-2026:87042** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87042)
- **RHSA-2026:87043** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87043)
- **RHSA-2026:87245** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8) · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:87245)
- **RHSA-2026:89884** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89884)
- **RHSA-2026:88397** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-10-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:88397)
- **RHSA-2026:89892** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89892)
- **RHSA-2026:89751** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89751)
- **RHSA-2026:89752** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89752)
- **RHSA-2026:89832** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89832)
