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CVE-2021-32671

51
FAUCET Score

CVE-2021-32671 is a critical cross-site scripting (XSS) vulnerability affecting Flarum forum software versions 1.0.0 and 1.0.1. The flaw allowed malicious HTML markup entered into user input fields, such as the search box, to be rendered as active DOM nodes, leading to client-side code execution. With a CVSS score of 10.0, this vulnerability poses a severe risk, enabling attackers to perform actions like deleting discussions, modifying user settings, or even compromising administrative panels if targeting privileged users. While no active exploitation or public exploit code has been identified, and community discussion is minimal, immediate patching to Flarum v1.0.2 is strongly recommended due to the high potential impact.

Impacted Technologies

VendorProductVersion(s)CPE
1.0.0CPE matchmatch criteria
cpe:2.3:a:flarum:flarum:1.0.0:*:*:*:*:*:*:*
1.0.1CPE matchmatch criteria
cpe:2.3:a:flarum:flarum:1.0.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

10.0CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
39.74%
Probability of exploitation in next 30 days
EPSS Percentile
98.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.3974 is in the 96th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

composerpatch availablevia ghsa
Product: flarum/coreFixed in: 1.0.2
github_advisorypatch availablevia nvd_reference
View patch

Vendor Advisories (1)

composerGHSA-5qjq-69w6-fg57critical

XSS vulnerability with translator

Jun 7, 2021

References

github.com / flarum/core/commit/440bed81b8019dff00642c8f493b4909d505a28a
PatchThird Party Advisory
github.com / flarum/core/security/advisories/GHSA-5qjq-69w6-fg57
Third Party Advisory
packagist.org / packages/flarum/core
ProductThird Party Advisory