---
id: CVE-2026-8286
title: |-
  A vulnerability exists where a new transfer that uses STARTTLS to upgrade the
  connection might reuse an existing live connection even though the TLS
  configuration mismatches so it should not.
summary: |-
  A vulnerability exists where a new transfer that uses STARTTLS to upgrade the
  connection might reuse an existing live connection even though the TLS
  configuration mismatches so it should not.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-295
vendor: haxx
product: curl
affected:
  - 'curl >= 7.30.0, < 8.21.0'
patched:
  - curl 8.21.0
published: '2026-07-03'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T07:16:31.617'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8286'
references:
  - url: 'https://curl.se/docs/CVE-2026-8286.html'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://curl.se/docs/CVE-2026-8286.json'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3718195'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3718195'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8286.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-8286'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2496763'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-8286'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8286'
  - url: 'https://access.redhat.com/errata/RHSA-2026:60440'
  - url: 'https://access.redhat.com/errata/RHSA-2026:55450'
  - url: 'https://access.redhat.com/errata/RHSA-2026:55439'
  - url: 'https://access.redhat.com/errata/RHSA-2026:57462'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63140'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63135'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63138'
  - url: 'https://access.redhat.com/errata/RHSA-2026:61783'
  - url: 'https://access.redhat.com/errata/RHSA-2026:29017'
  - url: 'https://access.redhat.com/errata/RHSA-2026:34975'
  - url: 'https://access.redhat.com/errata/RHSA-2026:56869'
  - url: 'https://access.redhat.com/errata/RHSA-2026:62260'
  - url: 'https://access.redhat.com/errata/RHSA-2026:58981'
  - url: 'https://access.redhat.com/errata/RHSA-2026:66018'
  - url: 'https://access.redhat.com/errata/RHSA-2026:66357'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-07-06T17:33:16.174641Z'
epss: 0.00309
epssPercentile: 0.23993
ingestedAt: '2026-07-04T04:55:39.432Z'
---

## Overview

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the
connection might reuse an existing live connection even though the TLS
configuration mismatches so it should not.

## Affected

- `curl >= 7.30.0, < 8.21.0`

## Remediation

Upgrade past the affected range:

- `curl 8.21.0`

## Vendor advisories

- **RHSA-2026:60440** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-09-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:60440)
- **RHSA-2026:55450** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-08-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:55450)
- **RHSA-2026:55439** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-08-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:55439)
- **RHSA-2026:57462** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57462)
- **RHSA-2026:63140** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.19 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63140)
- **RHSA-2026:63135** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.19 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63135)
- **RHSA-2026:63138** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.19 · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63138)
- **RHSA-2026:61783** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:61783)
- **RHSA-2026:29017** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-06-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:29017)
- **RHSA-2026:34975** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:34975)
- **RHSA-2026:56869** · Red Hat · fixed in: Red Hat JBoss Core Services 2.4.62.SP5 · released 2026-08-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:56869)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8286.json)
- **RHSA-2026:66357** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:66357)
