CVE-2021-24856Public exploitNetwork attack vector

Stored script execution via unescaped counter text

Published Nov 17, 2021 · Updated Aug 3, 2024

Stored XSS in Tammersoft Shared Files before 1.6.61 allows remote authenticated users to execute script through Download Counter Text. The plugin stores that setting without sanitization and emits it without escaping when a page renders the [shared_files] shortcode with the counter enabled and at least one file. A high-privilege user can plant script even when unfiltered_html is disabled, and execution requires another user to view the affected file list.

CVSS severity4.8
Medium
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Tammersoft Shared Files before 1.6.61 allows remote authenticated users to execute script through Download Counter Text. The plugin stores that setting without sanitization and emits it without escaping when a page renders the [shared_files] shortcode with the counter enabled and at least one file. A high-privilege user can plant script even when unfiltered_html is disabled, and execution requires another user to view the affected file list.

The record

CVE
CVE-2021-24856
Published
Nov 17, 2021
Updated
Aug 3, 2024
Vendor
Tammersoft
Product
Shared Files
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Nov 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.6.61 <1.6.61

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Tammersoft · Shared Filesversion=1.6.61 <1.6.61

Published CVSS scores

3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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