CVE-2026-33169

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. `NumberToDelimitedConverter` uses a lookahead-based regular expression with `gsub!` to insert thousands delimiters. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the interaction between the repeated lookahead group and `gsub!` can produce quadratic time complexity on long digit strings. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

The following products are affected by CVE-2026-33169 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33169.

URL	Resource
https://github.com/rails/rails/commit/29154f1097da13d48fdb3200760b3e3da66dcb11
https://github.com/rails/rails/commit/b54a4b373c6f042cab6ee2033246b1c9ecc38974
https://github.com/rails/rails/commit/ec1a0e215efd27a3b3911aae6df978a80f456a49
https://github.com/rails/rails/releases/tag/v7.2.3.1
https://github.com/rails/rails/releases/tag/v8.0.4.1
https://github.com/rails/rails/releases/tag/v8.1.2.1
https://github.com/rails/rails/security/advisories/GHSA-cg4j-q9v8-6v38
https://nvd.nist.gov/vuln/detail/CVE-2026-33169
https://www.cve.org/CVERecord?id=CVE-2026-33169