CVE-2018-20583

mediumpriority · track · 25EPSS 0.019 · 79 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.86% (79th) EPSS

CVSS 4.3 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML (even if allow_unsafe_links is false) via a newline character (e.g., writing javascript as javascri%0apt).

cvss

Technical severity, 0–10. One row per scoring source.

6.1

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.06.1mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 2.7

v3.06.1mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nsecondary · OSV

v3.05.6mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimaryCWE-79US

affected products (3)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
thephpleague commonmark0.15.6 → 0.18.0nvdUScpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:*
Packagist league/commonmark0.15.6 → 0.18.1osvUSpkg:composer/league/commonmark

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-qx76-c53f-5c7qPHP League CommonMark vulnerable to Cross-Site Scripting (XSS)2022-05-14ghsa · osvUS
Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML (even if allow_unsafe_links is false) via a newline character (e.g., writing javascript as javascri%0apt).

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2018-12-30modified 2026-06-17

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+53016 more

references (9)

External citations — patches, advisories, analysis.

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