Stored XSS by authenticated backend user with access to upload files

中 5.4CVE-2020-15249 · GHSA-fx3v-553x-3c4q · 23/11/2020 公開 · 17/06/2026 更新

要点

CVE-2020-15249 は october/backend, october (octobercms) に影響する深刻度「中」 (CVSS 5.4) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.46%（全脆弱性の 40.3% より高い）。
対処：1.0.469 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
october/backend Packagist	`≥ 1.0.319, < 1.0.469`	`1.0.469`
october octobercms	`≥ 1.0.319, < 1.0.469`	`1.0.469`

概要

Impact

Backend users with access to upload files were permitted to upload SVG files without any sanitization applied to the uploaded files. Since SVG files support being parsed as HTML by browsers, this means that they could theoretically upload Javascript that would be executed on a path under the website's domain (i.e. /storage/app/media/evil.svg), but they would have to convince their target to visit that location directly in the target's browser as the backend does not display SVGs inline anywhere, SVGs are only displayed as image resources in the backend and are thus unable to be executed.

Patches

Issue has been patched in Build 469 (v1.0.469) & v1.1.0.

Workarounds

Apply https://github.com/octobercms/library/commit/80aab47f044a2660aa352450f55137598f362aa4 to your installation manually if unable to upgrade to Build 469 or v1.1.0.

References

Reported by Hoan Hoang

For more information

If you have any questions or comments about this advisory:

Email us at [email protected]

Threat assessment:

NVD の説明

October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. In October CMS from version 1.0.319 and before version 1.0.469, backend users with access to upload files were permitted to upload SVG files without any sanitization applied to the uploaded files. Since SVG files support being parsed as HTML by browsers, this means that they could theoretically upload Javascript that would be executed on a path under the website's domain (i.e. /storage/app/media/evil.svg), but they would have to convince their target to visit that location directly in the target's browser as the backend does not display SVGs inline anywhere, SVGs are only displayed as image resources in the backend and are thus unable to be executed. Issue has been patched in Build 469 (v1.0.469) & v1.1.0.