Symfony: ReDoS in HeaderUtils::split() Reachable Through the Cache-Control Request Header
Summary
| CVE | CVE-2026-108082 |
|---|---|
| State | PUBLISHED |
| Assigner | Checkmarx |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-15 15:17:22 UTC |
| Updated | 2026-10-16 16:00:33 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 8.7 HIGH from 596c5446-0ce5-4ba2-aa66-48b3b757a647
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-1333 | CWE-1333 CWE-1333 Inefficient regular expression complexity
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 596c5446-0ce5-4ba2-aa66-48b3b757a647 | Secondary | 8.7 | HIGH | 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/E:X/C... |
| 4.0 | CNA | CVSS | 8.7 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Sensiolabs | Symfony | affected v4.1.0-BETA1 v5.4.54 git | Not specified |
| CNA | Sensiolabs | Symfony | affected v6.0.0-BETA1 v6.4.46 git | Not specified |
| CNA | Sensiolabs | Symfony | affected v7.0.0-BETA1 v7.4.19 git | Not specified |
| CNA | Sensiolabs | Symfony | affected v8.0.0-BETA1 v8.1.7 git | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| symfony.com/blog/cve-2026-108082-redos-in-headerutils-split-reachable-thr... | 596c5446-0ce5-4ba2-aa66-48b3b757a647 | symfony.com | |
| github.com/symfony/symfony/pull/66491 | 596c5446-0ce5-4ba2-aa66-48b3b757a647 | github.com | |
| github.com/symfony/symfony/security/advisories/GHSA-r925-mgvr-h9cc | 596c5446-0ce5-4ba2-aa66-48b3b757a647 | github.com | |
| github.com/symfony/symfony/pull/66048 | 596c5446-0ce5-4ba2-aa66-48b3b757a647 | github.com | |
| 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: r3verii (en)
CNA: Duarte Santos (en)
CNA: Nicolas Grekas (en)
There are currently no legacy QID mappings associated with this CVE.