CVE-2020-13756

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 55.1%, top 1% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 55%
CISA-KEV: Not listedEPSS: 55%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
71(Track*)
EG Risk 71/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation55% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
98.9%
KEV
Not listed

Published

June 3, 2020

Last Modified

November 3, 2025

Advisory Details (4)

Auto-updated Jun 14, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit.
generic Patch Available

[SECURITY] [DLA 4333-1] php-horde-css-parser security update

https://lists.debian.org/debian-lts-announce/2025/10/msg00013.html
github_commit Patch Available

commit 2ebf59e8bfbf (sabberworm/PHP-CSS-Parser)

Patch available: sabberworm/PHP-CSS-Parser 8.4.0 (contains commit 2ebf59e8bfbf)

https://github.com/sabberworm/PHP-CSS-Parser/commit/2ebf59e8bfbf6cfc1653a5f0ed743b95062c62a4
generic Patch Available🟡 PoC Available

Full Disclosure: Sabberworm PHP CSS parser - Code injection vulnerability

http://seclists.org/fulldisclosure/2020/Jun/7
generic

Packet Storm

http://packetstormsecurity.com/files/157923/Sabberworm-PHP-CSS-Code-Injection.html

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuphp-horde-css-parser (1.0.11-1ubuntu1+esm1) @ bionic2026-05-27ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
sabberworm/php-css-parser1.0.01.0.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 14:15 UTCEPSS rescore
  3. 2026-07-23 01:49 UTCEG score recompute
  4. 2026-07-22 22:34 UTCEG score recompute
  5. 2026-07-22 14:05 UTCEPSS rescore
  6. 2026-07-21 15:22 UTCEPSS rescore
  7. 2026-07-21 15:22 UTCEPSS rescore
  8. 2026-07-20 17:04 UTCEPSS rescore
  9. 2026-07-19 11:52 UTCOSV refresh
  10. 2026-07-19 02:26 UTCEPSS rescore
  11. 2026-07-19 02:26 UTCEPSS rescore
  12. 2026-07-18 10:02 UTCEPSS rescore
  13. 2026-07-16 16:59 UTCEPSS rescore
  14. 2026-07-16 16:59 UTCEPSS rescore
  15. 2026-07-15 16:55 UTCEPSS rescore
  16. 2026-07-13 22:27 UTCEPSS rescore
  17. 2026-07-13 06:10 UTCEPSS rescore
  18. 2026-07-13 06:10 UTCEPSS rescore
  19. 2026-07-12 05:44 UTCEPSS rescore
  20. 2026-07-11 08:24 UTCEPSS rescore
  21. 2026-07-09 19:06 UTCEPSS rescore
  22. 2026-07-08 15:11 UTCEPSS rescore
  23. 2026-07-06 02:20 UTCEPSS rescore
  24. 2026-07-04 06:28 UTCEPSS rescore
  25. 2026-07-01 20:01 UTCOSV refresh
Show 54 more
  1. 2026-07-01 15:03 UTCEPSS rescore
  2. 2026-07-01 15:03 UTCEPSS rescore
  3. 2026-06-30 23:20 UTCEPSS rescore
  4. 2026-06-30 23:20 UTCEPSS rescore
  5. 2026-06-28 04:54 UTCEPSS rescore
  6. 2026-06-28 04:54 UTCEPSS rescore
  7. 2026-06-27 03:06 UTCEPSS rescore
  8. 2026-06-25 13:47 UTCEPSS rescore
  9. 2026-06-25 13:47 UTCEPSS rescore
  10. 2026-06-24 14:03 UTCEPSS rescore
  11. 2026-06-24 14:03 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-23 21:31 UTCEPSS rescore
  14. 2026-06-21 14:54 UTCEPSS rescore
  15. 2026-06-21 14:54 UTCEPSS rescore
  16. 2026-06-21 01:57 UTCEPSS rescore
  17. 2026-06-21 01:57 UTCEPSS rescore
  18. 2026-06-18 17:50 UTCEPSS rescore
  19. 2026-06-18 17:50 UTCEPSS rescore
  20. 2026-06-17 17:50 UTCEPSS rescore
  21. 2026-06-17 17:50 UTCEPSS rescore
  22. 2026-06-16 17:50 UTCEPSS rescore
  23. 2026-06-16 17:50 UTCEPSS rescore
  24. 2026-06-15 17:46 UTCEPSS rescore
  25. 2026-06-14 23:15 UTCEPSS rescore
  26. 2026-06-14 23:15 UTCEPSS rescore
  27. 2026-06-14 02:13 UTCOSV refresh
  28. 2026-06-12 23:09 UTCEPSS rescore
  29. 2026-06-11 13:58 UTCEPSS rescore
  30. 2026-06-10 22:16 UTCEPSS rescore
  31. 2026-06-10 22:16 UTCEPSS rescore
  32. 2026-06-10 13:20 UTCEPSS rescore
  33. 2026-06-07 15:23 UTCEPSS rescore
  34. 2026-06-07 15:23 UTCEPSS rescore
  35. 2026-06-06 13:45 UTCEPSS rescore
  36. 2026-06-06 13:45 UTCEPSS rescore
  37. 2026-06-06 13:45 UTCEPSS rescore
  38. 2026-06-05 22:45 UTCEPSS rescore
  39. 2026-06-05 22:45 UTCEPSS rescore
  40. 2026-06-02 20:11 UTCEPSS rescore
  41. 2026-06-02 20:11 UTCEPSS rescore
  42. 2026-06-01 13:50 UTCEPSS rescore
  43. 2026-05-31 22:29 UTCEPSS rescore
  44. 2026-05-31 22:29 UTCEPSS rescore
  45. 2026-05-29 13:42 UTCEPSS rescore
  46. 2026-05-29 13:42 UTCEPSS rescore
  47. 2026-05-28 13:43 UTCEPSS rescore
  48. 2026-05-28 13:43 UTCEPSS rescore
  49. 2026-05-27 13:39 UTCEPSS rescore
  50. 2026-05-27 03:05 UTCEG score recompute
  51. 2026-05-27 03:05 UTCVendor advisory
  52. 2026-05-26 13:42 UTCEPSS rescore
  53. 2026-05-26 13:42 UTCEPSS rescore
  54. 2026-05-26 12:15 UTCOSV refresh

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2020-13756?
CVE-2020-13756 is a critical vulnerability published on June 3, 2020. 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.
When was CVE-2020-13756 disclosed?
CVE-2020-13756 was first published in the National Vulnerability Database on June 3, 2020, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-13756 actively exploited?
CVE-2020-13756 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-13756?
CVE-2020-13756 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-13756?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-13756, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2020-13756

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