CVE-2026-45066

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 78% 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
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: None knownExposed: 0

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

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

May 27, 2026

Last Modified

July 16, 2026

Advisory Details (5)

Auto-updated Jul 15, 2026
Patch available. Sources: github_release, github, github_commit.
github Patch Available

HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and <area> Misclassification · Advisory · symfony/symfony · GitHub

https://github.com/symfony/symfony/security/advisories/GHSA-qc95-4862-92fh
github_release Patch Available

v8.0.12

Patch available: symfony/symfony v8.0.12

https://github.com/symfony/symfony/releases/tag/v8.0.12
github_release Patch Available

v7.4.12

Patch available: symfony/symfony v7.4.12

https://github.com/symfony/symfony/releases/tag/v7.4.12
github_release Patch Available

v6.4.40

Patch available: symfony/symfony v6.4.40

https://github.com/symfony/symfony/releases/tag/v6.4.40
github_commit

commit d506b556d3d3 (symfony/symfony)

Fix landed in symfony/symfony commit d506b556d3d3 — awaiting tagged release

https://github.com/symfony/symfony/commit/d506b556d3d3906f3e8660ad82257ce87edbaac4

Vendor Advisories for CVE-2026-45066(1)

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

Affected Packages

(2 across 1 ecosystem)
Packagist(2)
PackageVulnerable rangeFixed inDependents
symfony/html-sanitizerv8.0.0, v8.0.7, v8.0.88.0.12—
symfony/symfonyv8.0.0 ... v8.0.9 (12 versions)8.0.12—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 20× 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. 2026-07-27 10:02 UTCEG score recompute
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-26 14:54 UTCEPSS rescore
  4. 2026-07-25 14:18 UTCEPSS rescore
  5. 2026-07-24 14:17 UTCEPSS rescore
  6. 2026-07-23 14:18 UTCEPSS rescore
  7. 2026-07-23 03:16 UTCEG score recompute▲ 3.80
  8. 2026-07-22 14:08 UTCEPSS rescore
  9. 2026-07-21 15:24 UTCEPSS rescore
  10. 2026-07-20 17:08 UTCEPSS rescore
  11. 2026-07-19 14:31 UTCEPSS rescore
  12. 2026-07-19 02:29 UTCEPSS rescore
  13. 2026-07-18 10:04 UTCEPSS rescore
  14. 2026-07-16 17:03 UTCEPSS rescore
  15. 2026-07-16 16:30 UTCNVD updateCVSS v3 → 6.1 · severity → MEDIUM
  16. 2026-07-16 14:44 UTCMITRE cvelistV5CVSS v3 → 2.3 · severity → LOW
  17. 2026-07-15 16:57 UTCEPSS rescore
  18. 2026-07-15 14:22 UTCNVD updateCVSS v3 → 6.1 · severity → MEDIUM
  19. 2026-07-14 18:07 UTCEG score recompute▲ 2.30
  20. 2026-07-14 18:05 UTCMITRE cvelistV5CVSS v3 → 2.3 · CVSS v4 → 2.3 · severity → LOW
  21. 2026-06-14 23:18 UTCEPSS rescore
  22. 2026-06-13 23:00 UTCEPSS rescore
  23. 2026-06-12 23:12 UTCEPSS rescore
  24. 2026-05-27 20:35 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45066?
CVE-2026-45066 is a medium vulnerability published on May 27, 2026. Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC…
When was CVE-2026-45066 disclosed?
CVE-2026-45066 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on July 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45066 actively exploited?
CVE-2026-45066 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 78.0% of all scored CVEs.
What is the CVSS score of CVE-2026-45066?
CVE-2026-45066 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-45066?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45066, 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

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