CVE-2026-108082 Affecting nextcloud-server-34 package, versions <34.0.5-r7


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.48% (42nd percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-NEXTCLOUDSERVER34-21831227
  • published30 Oct 2026
  • disclosed15 Oct 2026

Introduced: 15 Oct 2026

NewCVE-2026-108082  (opens in a new tab)

How to fix?

Upgrade Chainguard nextcloud-server-34 to version 34.0.5-r7 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nextcloud-server-34 package and not the nextcloud-server-34 package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

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.