CVE-2026-64851

HIGHPre-NVD 8.58.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 74% 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, secondary
Elevated
8.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.5Exploit: Elevated riskExposed: 0

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

Grav Shortcode Core Plugin allows for the development shortcode plugins that utilize the common format utilized by WordPress and BBCode. Prior to 6.2.2, Grav Shortcode Core passes shortcode syntax through Security::detectXss() because it contains no literal less-than character, then ColorShortcode.php and related attribute handlers concatenate an attacker-controlled parameter into HTML without encoding. An account with admin.pages permission can close the generated attribute and add an event handler, creating stored cross-site scripting that executes for visitors or administrators who view the page. This issue is fixed in version 6.2.2.

CVSS v3
8.5
EG Score
8.5(medium)
EG Risk
54(Track*)
EG Risk 54/100SSVC: 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
Severity85% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

August 19, 2026

Last Modified

August 19, 2026

Advisory Details (3)

Auto-updated Aug 19, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

6.2.2

Patch available: getgrav/grav-plugin-shortcode-core 6.2.2

https://github.com/getgrav/grav-plugin-shortcode-core/releases/tag/6.2.2
github_commit Patch Available

commit 2a55eac8a2cc (getgrav/grav-plugin-shortcode-core)

Patch available: getgrav/grav-plugin-shortcode-core 6.2.2 (contains commit 2a55eac8a2cc)

https://github.com/getgrav/grav-plugin-shortcode-core/commit/2a55eac8a2cc7f6c2d4923ab2fa7991039620597
github Patch Available🟡 PoC Available

Stored XSS in shortcode-core attribute handlers · Advisory · getgrav/grav · GitHub

https://github.com/getgrav/grav/security/advisories/GHSA-q5fw-vpqc-fgph

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 21× 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. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 01:55 UTCEG score recompute
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-27 18:45 UTCEG score recompute
  5. 2026-08-26 18:42 UTCEG score recompute
  6. 2026-08-26 14:47 UTCEPSS rescore
  7. 2026-08-25 20:08 UTCEG score recompute
  8. 2026-08-25 13:49 UTCEPSS rescore
  9. 2026-08-24 21:34 UTCEG score recompute
  10. 2026-08-24 10:18 UTCEG score recompute
  11. 2026-08-23 00:26 UTCEG score recompute
  12. 2026-08-23 00:19 UTCEPSS rescore
  13. 2026-08-22 01:51 UTCEG score recompute
  14. 2026-08-21 23:49 UTCEPSS rescore
  15. 2026-08-21 03:17 UTCEG score recompute
  16. 2026-08-20 22:55 UTCEPSS rescore
  17. 2026-08-19 17:23 UTCEG score recompute
  18. 2026-08-19 16:45 UTCEG score recompute
  19. 2026-08-19 16:24 UTCEG score recompute
  20. 2026-08-19 16:03 UTCEG score recompute
  21. 2026-08-19 16:02 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-64851?
CVE-2026-64851 is a high vulnerability published on August 19, 2026. Grav Shortcode Core Plugin allows for the development shortcode plugins that utilize the common format utilized by WordPress and BBCode. Prior to 6.2.2, Grav Shortcode Core passes shortcode syntax through Security::detectXss() because it contains no literal less-than character, then…
When was CVE-2026-64851 disclosed?
CVE-2026-64851 was first published in the National Vulnerability Database on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64851 actively exploited?
CVE-2026-64851 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 73.7% of all scored CVEs.
What is the CVSS score of CVE-2026-64851?
CVE-2026-64851 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2026-64851?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64851, 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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