CVE-2020-13756PHP Css Parser Code Injection
Sabberworm PHP CSS Parser Code injection vulnerability in allSelectors()
Published Mar 26, 2022 · Updated Aug 27, 2026 · Also known as DEBIAN-CVE-2020-13756, DLA-4333-1, GHSA-phrq-v4q2-hmq6, UBUNTU-CVE-2020-13756, USN-7502-1
Key Facts
Patch immediately- CVE-2020-13756 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting PHP Css Parser (Sabberworm), sabberworm/php-css-parser (composer), php-horde-css-parser (debian).
- It is exploited in the wild, listed in Industry KEV feed since Jan 12, 2022. No public exploit code is known.
- EPSS estimates a 50% probability of exploitation in the next 30 days.
- Fixed versions are available, including php-horde-css-parser 1.0.11-1ubuntu1+esm1, php-horde-css-parser 1.0.11-8.1, php-horde-css-parser 1.0.11-8+deb11u1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
50%
Higher than 98.8% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
49/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Jan 12, 2022
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
3
Reports of active use
Advisories And Exploit References
- advisoryhttps://github.com/FriendsOfPHP/security-advisories/blob/master/sabberworm/php-css-parser/CVE-2020-13756.yaml
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2020-13756
- advisoryhttps://packetstormsecurity.com/files/cve/CVE-2020-13756
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2020-13756
- advisoryhttps://ubuntu.com/security/CVE-2020-13756
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2020-13756
Description
Sabberworm PHP CSS Parser before 8.3.1 calls eval on uncontrolled data, possibly leading to remote code execution if the function allSelectors() or getSelectorsBySpecificity() is called with input from an attacker.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Jan 12, 2022 | n/a | Not reported |
Affected Products
13 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| PHP Css ParserSabberworm | See advisory | 8.3.1 |
| sabberworm/php-css-parsercomposer | >= 1.0.0 | 1.0.1 |
| php-horde-css-parserdebian | See advisory | 1.0.11-8+deb11u1 |
Patched Releases
php-horde-css-parser
1.0.11-1ubuntu1+esm1, 1.0.11-8.1, 1.0.11-8+deb11u1, 1.0.8-1ubuntu1+esm1
PHP Css Parser
8.3.1
sabberworm/php-css-parser
1.0.1, 2.0.1, 3.0.1, 4.0.1, 5.0.9, 5.1.3, 5.2.1, 6.0.2, 7.0.4, 8.0.1, 8.1.1, 8.2.1, 8.3.1
Timeline
Added to Industry KEV feed
Jan 12, 2022
Publicly disclosed
Mar 26, 2022
Last updated
Aug 27, 2026
Weakness Type
- CWE-20 Improper Input Validation
- CWE-94 Improper Control of Generation of Code ('Code Injection')
References
- advisorygithub.com · CVE-2020-13756
- advisorynvd.nist.gov · CVE-2020-13756
- advisorypacketstormsecurity.com · CVE-2020-13756
- advisorysecurity-tracker.debian.org · CVE-2020-13756
- advisoryubuntu.com · CVE-2020-13756
FAQ
Common Questions.
Sabberworm PHP CSS Parser before 8.3.1 calls eval on uncontrolled data, possibly leading to remote code execution if the function allSelectors() or getSelectorsBySpecificity() is called with input from an attacker.
Affected: PHP Css Parser (Sabberworm); sabberworm/php-css-parser (composer) versions >= 1.0.0; php-horde-css-parser (debian). The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Jan 12, 2022.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including php-horde-css-parser 1.0.11-1ubuntu1+esm1, php-horde-css-parser 1.0.11-8.1, php-horde-css-parser 1.0.11-8+deb11u1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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