CVE-2026-104021

HIGHPre-NVD 7.27.2—
EchelonGraph scoreHIGH confidence

Score 7.2 from GitHub Security Advisory (severity: HIGH) published 2026-10-10. A secondary CVSS source baseline 7.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
Trending — 4 sources updated this week
7.2EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.2Exploit: None knownExposed services: Not assessed

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

The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcache_settings[cache_cookie_exclude][] parameter. This is due to the plugin registering the cache_cookie_exclude setting via register_setting() without a sanitize_callback, while buildSiteHtaccessRules() applies only trim() to each cookie value before interpolating it directly into an Apache RewriteCond line — a normalization that strips surrounding whitespace but leaves embedded newlines intact, allowing an attacker to break out of the capture group and append arbitrary directives. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary Apache directives into the site's .htaccess file via file_put_contents(), enabling server-level configuration changes such as setting php_value auto_prepend_file to execute attacker-controlled PHP code on every request.

CVSS v3
7.2
EG Score
7.2HIGHhigh confidence
EG Risk
37
EG Risk 37/100CISA SSVC

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
Severity72% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.4%
EPSS %ILE
32nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 10, 2026

Last Modified

October 10, 2026

References (7)

Vendor Advisories for CVE-2026-104021(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 6× 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. 2026-10-10 19:59 UTCEPSS rescore
  2. 2026-10-10 16:58 UTCEG score recompute
  3. 2026-10-10 16:58 UTCGHSA enrichment
  4. 2026-10-10 05:21 UTCEG score recompute
  5. 2026-10-10 04:31 UTCEG score recompute
  6. 2026-10-10 04:30 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-104021?
CVE-2026-104021 is a high vulnerability published on October 10, 2026. The Fastcache by Host.it plugin for WordPress is vulnerable to Code Injection in all versions up to, and including, 1.7.4 via the fastcachesettings[cachecookieexclude][] parameter. This is due to the plugin registering the cachecookieexclude setting via registersetting() without a sanitizecallback,…
When was CVE-2026-104021 disclosed?
CVE-2026-104021 was first published on October 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-104021 actively exploited?
CVE-2026-104021 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-104021?
CVE-2026-104021 has a CVSS base score of 7.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-104021?
No fix for CVE-2026-104021 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-104021 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-104021

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