CVE-2021-24956

Blog2Social <= 6.8.6 - Reflected Cross-Site Scripting

2021-11-22 00:00

Strategic Overview

Status: Patched in 6.8.7
Affected Plugin: Blog2Social: Social Media Auto Post & Scheduler
Affected Version: <= 6.8.6
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-24956

View all Blog2Social: Social Media Auto Post & Scheduler vulnerabilities

At a glance

CVE-2021-24956 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Blog2Social WordPress plugin, affecting versions <= 6.8.6. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 6.8.7; sites on affected versions should update now. Disclosed November 2021, reported by ZhongFu Su.

Vulnerability Overview

The Blog2Social: Social Media Auto Post & Scheduler WordPress plugin before 6.8.7 does not sanitise and escape the b2sShowByDate parameter before outputting it back in an admin page, leading to a Reflected Cross-Site Scripting issue

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Blog2Social <= 6.8.6 takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Blog2Social the fix is 6.8.7: builds <= 6.8.6 are affected, anything from 6.8.7 onward is not.

Remediation

Update to version 6.8.7, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Blog2Social: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Blog2Social 6.8.7 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24956 https://www.wordfence.com/threat-intel/vulnerabilities/id/7817f343-1ed6-4b76-afbe-1054de892422 https://nvd.nist.gov/vuln/detail/CVE-2021-24956

Related records

Same weakness class

Other vulnerabilities in Blog2Social: Social Media Auto Post & Scheduler

CVSS Vector

6.1

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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