How severe is CVE-2021-40926?

CVE-2021-40926 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-40926?

CVE-2021-40926 affects the following packages: james-heinrich/getid3 (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-40926?

Update james-heinrich/getid3 to 1.9.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40926 is resolved across your whole dependency graph.

How do I detect CVE-2021-40926 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for james-heinrich/getid3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-40926 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-40926 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-40926, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-40926?

CVE-2021-40926 has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 62th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-40926?

CVE-2021-40926 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-40926 published, and has it been updated?

CVE-2021-40926 was published on October 1, 2021 and was last updated on March 14, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2021-40926 — getid3

MEDIUMFix: JamesHeinrich/getID3#342

CVE-2021-40926 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in james-heinrich/getid3. 1 public exploit reference exists, so weaponization risk is real. A fix is available for james-heinrich/getid3 — see the affected versions and patch details below.

Cross-site scripting in demos/demo.mysqli.php in getID3

Also known asGHSA-x2gw-85w6-fjjw

Published

Oct 1, 2021

Updated

Mar 14, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs62th percentile — riskier than 62% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-40926 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐘james-heinrich/getid3

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Cross-site scripting (XSS) vulnerability in demos/demo.mysqli.php in getID3 1.X and v2.0.0-beta allows remote attackers to inject arbitrary web script or HTML via the showtagfiles parameter.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`james-heinrich/getid3`	≥ 1.0.0&&< 1.9.21	1.9.21`composer require james-heinrich/getid3:^1.9.21`

Affected Products

1 product · 2 configurations

Application

getid3getid3

≥ 1.9.0 && < 2.0.0

1 version

2.0.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Cross-site scripting (XSS) vulnerability in demos/demo.mysqli.php in get…

github.comNVDOct 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for james-heinrich/getid3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update james-heinrich/getid3 to 1.9.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40926 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

Cross-site scripting (XSS) vulnerability in demos/demo.mysqli.php in getID3 1.X and v2.0.0-beta allows remote attackers to inject arbitrary web script or HTML via the showtagfiles parameter.

O3 Security · Impact-Aware SCA

Is CVE-2021-40926 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

getID3

4.3/10

Maintained10/10

Code-Review4/10

Branch-Protection0/10

Assessed Oct 5, 2026

Timeline

Disclosed

Oct 1, 2021

First exploit

Oct 4, 2021

3 days after disclosure — rapid exploitation

Last updated

Mar 14, 2026

Identifiers

CVE-2021-40926

GHSA-x2gw-85w6-fjjw

References

Advisorygithub.com Advisorynvd.nist.gov Reportgithub.com Webgithub.com Webgithub.com

Related vulnerabilities

Also affects james-heinrich/getid3

This CVE is medium severity; 1 of 1 other CVE affecting james-heinrich/getid3 is rated as high or higher (top: high).

CVE-2014-2053

Same weakness: CWE-79

This CVE is medium severity; 7 of 7 other CVEs with CWE-79 are rated as high or higher (top: high).

CVE-2026-91127CVE-2026-77606CVE-2026-84992CVE-2026-77608CVE-2026-77607GHSA-9rcc-pmj8-ffhrCVE-2026-77616Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedMar 14, 2026