CVE-2026-44312

MEDIUMNVD 5.85.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.8 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 96% 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
Elevated
5.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

css_parser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFY_NONE, meaning any HTTPS certificate—even entirely untrusted—will be accepted without validation. This vulnerability is fixed in 2.1.0 and 1.22.0.

CVSS v3
5.8
EG Score
5.8(medium)
EPSS
4.3%
KEV
Not listed

Published

May 14, 2026

Last Modified

May 15, 2026

Advisory Details (4)

Auto-updated Jun 16, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

css_parser allows to MITM included https css urls · Advisory · premailer/css_parser · GitHub

https://github.com/premailer/css_parser/security/advisories/GHSA-ff6c-w6qf-7xqc
generic

[SECURITY] CSS Parser Has http.verify_mode = OpenSSL::SSL::VERIFY_NONE · Issue #185 · premailer/css_parser · GitHub

https://github.com/premailer/css_parser/issues/185
github_commit

commit e0c95d5abe91 (premailer/css_parser)

Fix landed in premailer/css_parser commit e0c95d5abe91 — awaiting tagged release

https://github.com/premailer/css_parser/commit/e0c95d5abe91b237becb90ff316531a6547ada18
github_commit

commit 35e689c90422 (premailer/css_parser)

Fix landed in premailer/css_parser commit 35e689c90422 — awaiting tagged release

https://github.com/premailer/css_parser/commit/35e689c904225add78e0c488cf04bad052666449

Vendor Advisories for CVE-2026-44312(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
RubyGems(1)
PackageVulnerable rangeFixed inDependents
css_parser0.9.0 ... 1.9.0 (60 versions)1.22.0—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 30× 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. 2026-07-16 17:03 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-13 22:30 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-12 05:46 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 02:23 UTCEPSS rescore
  12. 2026-07-05 02:30 UTCEPSS rescore
  13. 2026-07-04 06:31 UTCEPSS rescore
  14. 2026-07-01 15:07 UTCEPSS rescore
  15. 2026-06-30 23:22 UTCEPSS rescore
  16. 2026-06-29 14:06 UTCEPSS rescore
  17. 2026-06-28 14:07 UTCEPSS rescore
  18. 2026-06-28 04:56 UTCEPSS rescore
  19. 2026-06-27 03:08 UTCEPSS rescore
  20. 2026-06-25 13:49 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-24 14:05 UTCEPSS rescore
  23. 2026-06-23 21:33 UTCEPSS rescore
  24. 2026-06-22 14:25 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
Show 44 more
  1. 2026-06-21 01:59 UTCEPSS rescore
  2. 2026-06-19 19:25 UTCEPSS rescore
  3. 2026-06-18 17:52 UTCEPSS rescore
  4. 2026-06-18 17:52 UTCEPSS rescore
  5. 2026-06-17 17:53 UTCEPSS rescore
  6. 2026-06-16 17:52 UTCEPSS rescore
  7. 2026-06-15 17:49 UTCEPSS rescore
  8. 2026-06-13 23:00 UTCEPSS rescore
  9. 2026-06-12 23:12 UTCEPSS rescore
  10. 2026-06-12 23:12 UTCEPSS rescore
  11. 2026-06-11 14:00 UTCEPSS rescore
  12. 2026-06-10 22:18 UTCEPSS rescore
  13. 2026-06-10 13:22 UTCEPSS rescore
  14. 2026-06-10 13:22 UTCEPSS rescore
  15. 2026-06-08 14:17 UTCEPSS rescore
  16. 2026-06-08 14:17 UTCEPSS rescore
  17. 2026-06-07 15:25 UTCEPSS rescore
  18. 2026-06-07 15:25 UTCEPSS rescore
  19. 2026-06-06 13:47 UTCEPSS rescore
  20. 2026-06-06 13:47 UTCEPSS rescore
  21. 2026-06-05 22:47 UTCEPSS rescore
  22. 2026-06-05 06:10 UTCEPSS rescore
  23. 2026-06-05 06:10 UTCEPSS rescore
  24. 2026-06-04 13:12 UTCEPSS rescore
  25. 2026-06-04 13:12 UTCEPSS rescore
  26. 2026-06-02 20:13 UTCEPSS rescore
  27. 2026-06-01 13:52 UTCEPSS rescore
  28. 2026-06-01 13:52 UTCEPSS rescore
  29. 2026-05-31 22:30 UTCEPSS rescore
  30. 2026-05-31 22:30 UTCEPSS rescore
  31. 2026-05-31 00:16 UTCEPSS rescore
  32. 2026-05-31 00:16 UTCEPSS rescore
  33. 2026-05-29 13:44 UTCEPSS rescore
  34. 2026-05-29 13:44 UTCEPSS rescore
  35. 2026-05-28 13:44 UTCEPSS rescore
  36. 2026-05-28 13:44 UTCEPSS rescore
  37. 2026-05-27 13:40 UTCEPSS rescore
  38. 2026-05-27 13:40 UTCEPSS rescore
  39. 2026-05-26 13:44 UTCEPSS rescore
  40. 2026-05-26 07:18 UTCEPSS rescore
  41. 2026-05-21 22:43 UTCEPSS rescore
  42. 2026-05-20 22:38 UTCEPSS rescore
  43. 2026-05-20 12:15 UTCEG score recompute
  44. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-44312?
CVE-2026-44312 is a medium vulnerability published on May 14, 2026. cssparser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFYNONE, meaning…
When was CVE-2026-44312 disclosed?
CVE-2026-44312 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44312 actively exploited?
CVE-2026-44312 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44312?
CVE-2026-44312 has a CVSS v3 base score of 5.8 (NVD).
How do I remediate CVE-2026-44312?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44312, 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-2026-44312

Explore →

Is Your Infrastructure Affected by CVE-2026-44312?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs