csirt@kutim:~/threat-intel/cve/CVE-2021-21283

Katalog CVE

CVSS 5.4 · Medium EPSS 0,79%

Kerentanan Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') pada flarum sticky. Skor CVSS 3.1 5.4 (Medium) menurut NVD.

Deskripsi (NVD)

Flarum is an open source discussion platform for websites. The "Flarum Sticky" extension versions 0.1.0-beta.14 and 0.1.0-beta.15 has a cross-site scripting vulnerability. A change in release beta 14 of the Sticky extension caused the plain text content of the first post of a pinned discussion to be injected as HTML on the discussion list. The issue was discovered following an internal audit. Any HTML would be injected through the m.trust() helper. This resulted in an HTML injection where <script> tags would not be executed. However it was possible to run javascript from other HTML attributes, enabling a cross-site scripting (XSS) attack to be performed. Since the exploit only happens with the first post of a pinned discussion, an attacker would need the ability to pin their own discussion, or be able to edit a discussion that was previously pinned. On forums where all pinned posts are authored by your staff, you can be relatively certain the vulnerability has not been exploited. Forums where some user-created discussions were pinned can look at the first post edit date to find whether the vulnerability might have been exploited. Because Flarum doesn't store the post content history, you cannot be certain if a malicious edit was reverted. The fix will be available in version v0.1.0-beta.16 with Flarum beta 16. The fix has already been back-ported to Flarum beta 15 as version v0.1.0-beta.15.1 of the Sticky extension. Forum administrators can disable the Sticky extension until they are able to apply the update. The vulnerability cannot be exploited while the extension is disabled.

Rincian

Terbit di NVD
26 Januari 2021
Terakhir diubah
17 Juni 2026
Status NVD
Modified
CVSS 3.1
5.4 (Medium), sumber NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
EPSS (30 hari)
0,79% peluang dieksploitasi; lebih tinggi dari 54,9% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
flarum sticky Versi 0.1.0 beta14
flarum sticky Versi 0.1.0 beta15

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

Sumber: NVD · CVE.org · EPSS. Halaman ini disusun otomatis dari data tersebut; pembaruan terakhir 5 Okt 2026, 20:10 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.