---
id: CVE-2026-108082
title: >-
  Symfony is a PHP framework for web and console applications and a set of
  reusable PHP components
summary: "Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to versions\_5.4.54,\_6.4.46,\_7.4.19, and\_8.1.7,\_HeaderUtils::split() parsed header values with a pattern whose token alternative also …"
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-1333
vendor: sensiolabs
product: symfony/http-foundation
affected:
  - symfony/http-foundation >= v4.1.0-BETA1 < v5.4.54
  - symfony/http-foundation >= v6.0.0-BETA1 < v6.4.46
  - symfony/http-foundation >= v7.0.0-BETA1 < v7.4.19
  - symfony/http-foundation >= v8.0.0-BETA1 < v8.1.7
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:17:19.470'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-108082'
references:
  - url: 'https://github.com/symfony/symfony/pull/66048'
    label: 596c5446-0ce5-4ba2-aa66-48b3b757a647
  - url: 'https://github.com/symfony/symfony/pull/66491'
    label: 596c5446-0ce5-4ba2-aa66-48b3b757a647
  - url: 'https://github.com/symfony/symfony/security/advisories/GHSA-r925-mgvr-h9cc'
    label: 596c5446-0ce5-4ba2-aa66-48b3b757a647
  - url: >-
      https://symfony.com/blog/cve-2026-108082-redos-in-headerutils-split-reachable-through-the-cache-control-request-header
    label: 596c5446-0ce5-4ba2-aa66-48b3b757a647
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-15T18:04:09.776300Z'
cvssSource: cna
ingestedAt: '2026-10-15T15:09:08.431Z'
---

## Overview

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to versions 5.4.54, 6.4.46, 7.4.19, and 8.1.7, HeaderUtils::split() parsed header values with a pattern whose token alternative also matched whitespace, followed by a (?<!\s) lookbehind. A run of whitespace placed before a separator could be divided among the iterations of the enclosing repetition in exponentially many ways, and the engine tried all of them before settling. HeaderBag calls it for the Cache-Control header whenever a Request is built, so any application handling HTTP requests is reachable, with no authentication.



A single request carrying such a header costs close to a second of CPU (813 ms for a run of 17 spaces in an 8 KB header on PHP 8.5, doubling with each extra space). From 18 spaces on, preg_match_all() gives up at pcre.backtrack_limit and split() returns an empty array, so every directive of the header is silently dropped.



This issue affects symfony/http-foundation v4.1.0-BETA1 through v5.4.53, v6.0.0-BETA1 through v6.4.45, v7.0.0-BETA1 through v7.4.18, and v8.0.0-BETA1 through v8.1.6.

## Remediation

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