CVE-2020-13756
Public exploit available. Not confirmed exploited in the wild yet. Fixed in 8.3.1.
What to do
Find your product and version, then upgrade to the build on the right.
- Packagist sabberworm/php-css-parserAffected: ≥ 8.3.0, < 8.3.1Upgrade to: 8.3.1Stated by: GitHub advisory
- Sabberworm Php Css ParserAffected: < 8.3.1Upgrade to: 8.3.1Stated by: NVD
Versions as the sources state them. Full version matrix after sign-in
Steps
Written by AI from the record- Check your PHP application's dependency list or lock file for Sabberworm PHP CSS Parser and identify its installed version.
- Upgrade to version 8.3.1 or later.
- Until upgraded, prevent untrusted users from supplying CSS that reaches selector-processing features.
- Review application and server logs for unexpected commands or file changes after upgrading.
composer require sabberworm/php-css-parser:^8.3.1What it is
From the CVE record
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.
In plain language
Written by AI from the recordSabberworm PHP CSS Parser versions before 8.3.1 can let attackers take over a website or application if it processes attacker-supplied style files, so affected small businesses should act soon.
CVE-2020-13756 is a CWE-94 remote code execution flaw where uncontrolled data reaches eval through allSelectors() or getSelectorsBySpecificity().
If you're affected
- Full application takeover
- Customer data exposure
- Website defacement
- Service disruption
- Ransomware risk
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
4 sources with a proof of concept or module.
Exploit links, PoCs and Metasploit modules after sign-in- EPSS
50% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
The patch came 123 days before any public exploit.
- EPSS band changehigh → moderateepss band change
- OpenVAS check added
- EPSS band changemoderate → high
- Public exploit / PoCsource: packetstorm
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Scored 9.8 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
Watch the software you run.
My Stack ranks new CVEs for your products by real-world exploitation, so the next serious one reaches you without reading every advisory.
We'll flag the next CVE, public exploit or patch for Packagist, not every advisory. This one: public exploit.
A free account adds
- The full version matrix and every affected product
- Exploit links, proofs of concept and Metasploit modules
- Email alerts for the products you watch
- The same data over REST API, MCP and CLI