CVE-2026-71478 — league/commonmark is a PHP library for parsing and rendering CommonMark Markdown.
Description
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
CVSS v3.1 base metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NMedium severity
Band computed from the CVSS base score, not the source's own label — so it means the same thing across every feed.
AV
Network
Attack Vector
AC
Low
Attack Complexity
PR
None
Privileges Required
UI
Required
User Interaction
S
Changed
Scope
C
Low
Confidentiality
I
Low
Integrity
A
None
Availability
References
- advisory[email protected]https://github.com/thephpleague/commonmark/commit/493a5aa7d65754b73846006eaff9c2c4431a8e2c
- advisory[email protected]https://github.com/thephpleague/commonmark/releases/tag/2.9.0
- advisory134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/thephpleague/commonmark/security/advisories/GHSA-29pj-957v-52mc
Related threats
same CWE or vendorCVE-2026-107801 — Jivejdon through 5.0 contains a stored cross-site scripting vulnerability that allows authenticated attackers to execute JavaScript by uploading at…
CVE-2026-107801 · 56m ago
CVE-2026-107800 — Jivejdon through 5.0 contains a stored cross-site scripting vulnerability that allows authenticated attackers to inject script into private short m…
CVE-2026-107800 · 56m ago
CVE-2026-107799 — Jivejdon through 5.0 contains a stored cross-site scripting vulnerability that allows authenticated attackers to inject script by posting unsanitiz…
CVE-2026-107799 · 56m ago
CVE-2026-107798 — jivejdon from commit 595d8d22 through commit ee67a65e contains a stored cross-site scripting vulnerability in the default-enabled TextStyle filter …
CVE-2026-107798 · 56m ago
CVE-2026-107797 — Jivejdon through 5.0 contains a reflected cross-site scripting vulnerability in application/message/postThread.jsp that allows attackers to inject …
CVE-2026-107797 · 56m ago
CVE-2026-107796 — Jivejdon from commit 5489372d through commit ee67a65e contains a reflected cross-site scripting vulnerability in application/query/taggedThreadList…
CVE-2026-107796 · 56m ago