CVE-2026-28289

CRITICALNVD 8.110.0
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 10.0 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: cna:github_m
Trending — 3 sources updated this weekWeaponized
10.0EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Metasploit, epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 31%CVSS: 8.1Exploit: Metasploit · epss top5pct · public exploitExposed: 0

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

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.

CVSS v3
8.1
EG Score
10.0(low)
EG Risk
86(Track)
EG Risk 86/100SSVC: 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
Severity100% × 45%
Exploitation65% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
31%
EPSS %ILE
98%
KEV
Not listed

Published

March 3, 2026

Last Modified

June 17, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github_commit Patch Available

commit f7bc16c56a6b (freescout-help-desk/freescout)

Patch available: freescout-help-desk/freescout 1.8.207 (contains commit f7bc16c56a6b)

https://github.com/freescout-help-desk/freescout/commit/f7bc16c56a6b13c06da52ad51fd666546b40818f
github Patch Available🟡 PoC Available

FreeScout 1.8.206 - Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Unauthenticated Remote Code Execution · Advisory · freescout-help-desk/freescout · GitHub

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-5gpc-65p8-ffwp

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 3× in last 7d / 3× 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. 2026-07-28 15:36 UTCEPSS rescore
  2. 2026-07-27 12:54 UTCEG score recompute
  3. 2026-07-27 12:50 UTCOSV refresh

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Metasploitexploit/multi/http/freescout_htaccess_rce✓ verified
    First seen Mar 1, 2026

    FreeScout Unauthenticated RCE via ZWSP .htaccess Bypass

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-28289?
CVE-2026-28289 is a critical vulnerability published on March 3, 2026. FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a…
When was CVE-2026-28289 disclosed?
CVE-2026-28289 was first published in the National Vulnerability Database on March 3, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28289 actively exploited?
CVE-2026-28289 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 31% probability of exploitation in the next 30 days, which ranks it in the top 1.9% of all scored CVEs.
What is the CVSS score of CVE-2026-28289?
CVE-2026-28289 has a CVSS v3 base score of 8.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 10.0. The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-28289?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28289, 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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