---
id: CVE-2026-80255
title: |-
  A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
  space (ascii code 32) immediately before the `Secure` attribute causes curl to
  store the cookie without its Secure flag
summary: |-
  A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
  space (ascii code 32) immediately before the `Secure` attribute causes curl to
  store the cookie without its Secure flag. The cookie might then wrongfully be
  sent …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-201
vendor: haxx
product: curl
affected:
  - 'curl >= 8.13.0, < 8.22.0'
patched:
  - curl 8.22.0
published: '2026-09-06'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T07:16:30.770'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80255'
references:
  - url: 'https://curl.se/docs/CVE-2026-80255.html'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://curl.se/docs/CVE-2026-80255.json'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3972395'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3972395'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T18:45:09.883106Z'
epss: 0.00684
epssPercentile: 0.50739
ingestedAt: '2026-09-07T11:09:35.679Z'
---

## Overview

A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
space (ascii code 32) immediately before the `Secure` attribute causes curl to
store the cookie without its Secure flag. The cookie might then wrongfully be
sent over plaintext HTTP on subsequent requests to the same host.

## Affected

- `curl >= 8.13.0, < 8.22.0`

## Remediation

Upgrade past the affected range:

- `curl 8.22.0`