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Fencer Vulns
critical 9.8

CVE-2020-13756 in the critical feed json

Sabberworm PHP CSS Parser Code injection vulnerability in allSelectors()

published 2020-06-03 6 y ago modified 2026-06-17 4 mo ago also GHSA-phrq-v4q2-hmq6 , EUVD-2022-1499

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
49.8%
EPSS 49.8% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist 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
  • sabberworm php_css_parser 8.3.1
  • php-horde-css-parser Ubuntu Pro 16.04 LTS 1.0.8-1ubuntu1+esm1
  • php-horde-css-parser Ubuntu Pro 18.04 LTS 1.0.11-1ubuntu1+esm1

ubuntu advisories UBUNTU-CVE-2020-13756

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-13756 updated cvss 8.1

php-PHP-CSS-Parser: evaluation of uncontrolled data can result in remote code execution

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

49.80% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • seclists.org http://seclists.org/fulldisclosure/2020/Jun/7 referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/157923/Sabberworm-PHP-CSS-Code-Injection.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist sabberworm/php-css-parser
>=8.3.0, <8.3.1
>=8.2.0, <8.2.1
>=8.1.0, <8.1.1
>=8.0.0, <8.0.1
>=7.0.0, <7.0.4
>=6.0.0, <6.0.2
>=5.2.0, <5.2.1
>=5.1.0, <5.1.3
>=5.0.0, <5.0.9
>=4.0.0, <4.0.1
>=3.0.0, <3.0.1
>=2.0.0, <2.0.1
>=1.0.0, <1.0.1
8.3.1
8.2.1
8.1.1
8.0.1
7.0.4
6.0.2
5.2.1
5.1.3
5.0.9
4.0.1
3.0.1
2.0.1
1.0.1

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.