How severe is CVE-2020-13870?

CVE-2020-13870 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-13870?

CVE-2020-13870 affects the following packages: verbb/comments (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2020-13870?

Update verbb/comments to 1.5.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13870 is resolved across your whole dependency graph.

How do I detect CVE-2020-13870 in my Packagist dependencies?

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

How do I mitigate CVE-2020-13870 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-2020-13870 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-13870 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-13870?

CVE-2020-13870 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th 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-2020-13870?

CVE-2020-13870 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-2020-13870 published, and has it been updated?

CVE-2020-13870 was published on June 5, 2020 and was last updated on October 20, 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-2020-13870 — comments

MEDIUM

CVE-2020-13870 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in verbb/comments. A fix is available for verbb/comments — see the affected versions and patch details below.

Comments plugin stored Cross-site Scripting (XSS) via an asset volume name

Also known asGHSA-69ww-wv3j-mhg4

Published

Jun 5, 2020

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐘verbb/comments

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

An issue was discovered in the Comments plugin before 1.5.5 for Craft CMS. There is stored XSS via an asset volume name.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`verbb/comments`	all versions	1.5.5`composer require verbb/comments:^1.5.5`

Affected Products

1 product · 1 configurations

Application

commentsverbb

< 1.5.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for verbb/comments, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update verbb/comments to 1.5.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13870 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

An issue was discovered in the Comments plugin before 1.5.5 for Craft CMS. There is stored XSS via an asset volume name.

O3 Security · Impact-Aware SCA

Is CVE-2020-13870 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.4/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Jun 5, 2020

Last updated

Oct 20, 2026

Identifiers

CVE-2020-13870

GHSA-69ww-wv3j-mhg4

References

Advisorygithub.com · CHANGELOG.md Advisorynvd.nist.gov · CVE 2020 13870 Packagegithub.com · comments

Related vulnerabilities

Also affects verbb/comments

This CVE is medium severity, in line with the other 2 CVEs affecting verbb/comments.

CVE-2020-13868CVE-2020-13869

Same weakness: CWE-79

This CVE is medium severity; 6 of 6 other CVEs with CWE-79 are rated as high or higher (top: critical).

CVE-2026-113787CVE-2026-44267CVE-2026-96632CVE-2026-9086CVE-2026-118246CVE-2026-118251Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026