CVE-2026-18856

MEDIUMPre-NVD 4.74.7—
EchelonGraph scoreHIGH confidence

Score 4.7 from GitHub Security Advisory (severity: LOW) published 2026-08-05. a secondary CVSS source baseline 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
4.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.7Exploit: Elevated riskExposed: 0

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

A vulnerability was determined in Poesis Rhymix CMS up to 2.1.33. This impacts the function procImporterAdminCheckXmlFile of the file modules/importer/importer.admin.controller.php of the component Data Import Module. This manipulation of the argument filename causes server-side request forgery. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 2.1.34 will fix this issue. It is recommended to upgrade the affected component.

CVSS v3
4.7
EG Score
4.7(high)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity47% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

August 5, 2026

Last Modified

August 12, 2026

Advisory Details (3)

Auto-updated Aug 5, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic
https://rhymix.org/files/attach/releases/rhymix-2.1.34.zip
generic

Rhymix - Rhymix 2.1.34 Release Notes [SECURITY]

https://rhymix.org/news/1948042
generic🟡 PoC Available

GitHub - MCzhao2006/Rhymix-SSRF-Report · GitHub

https://github.com/MCzhao2006/Rhymix-SSRF-Report

Vendor Advisories for CVE-2026-18856(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 19× in last 7d / 51× 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. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 01:36 UTCEG score recompute
  3. 2026-08-20 01:36 UTCGHSA enrichment
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-19 00:58 UTCEG score recompute
  6. 2026-08-19 00:58 UTCGHSA enrichment
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-18 00:20 UTCEG score recompute
  9. 2026-08-18 00:20 UTCGHSA enrichment
  10. 2026-08-17 13:47 UTCEPSS rescore
  11. 2026-08-16 23:39 UTCEG score recompute
  12. 2026-08-16 23:39 UTCGHSA enrichment
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-16 02:14 UTCEPSS rescore
  15. 2026-08-15 23:01 UTCEG score recompute
  16. 2026-08-15 23:01 UTCGHSA enrichment
  17. 2026-08-15 01:30 UTCEPSS rescore
  18. 2026-08-14 22:23 UTCEG score recompute
  19. 2026-08-14 22:23 UTCGHSA enrichment
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-13 21:45 UTCGHSA enrichment
  22. 2026-08-12 21:08 UTCEG score recompute
  23. 2026-08-12 21:08 UTCGHSA enrichment
  24. 2026-08-12 13:50 UTCEPSS rescore
  25. 2026-08-11 21:17 UTCEG score recompute
Show 26 more
  1. 2026-08-11 21:17 UTCGHSA enrichment
  2. 2026-08-11 13:42 UTCEPSS rescore
  3. 2026-08-11 00:00 UTCEPSS rescore
  4. 2026-08-10 20:39 UTCGHSA enrichment
  5. 2026-08-09 20:02 UTCEG score recompute
  6. 2026-08-09 20:02 UTCGHSA enrichment
  7. 2026-08-09 13:46 UTCEPSS rescore
  8. 2026-08-08 19:24 UTCEG score recompute
  9. 2026-08-08 19:24 UTCGHSA enrichment
  10. 2026-08-08 16:37 UTCEPSS rescore
  11. 2026-08-07 18:46 UTCEG score recompute
  12. 2026-08-07 18:46 UTCGHSA enrichment
  13. 2026-08-06 18:08 UTCEG score recompute
  14. 2026-08-06 18:08 UTCGHSA enrichment
  15. 2026-08-06 13:46 UTCEPSS rescore
  16. 2026-08-05 19:17 UTCEPSS rescore
  17. 2026-08-05 17:30 UTCEG score recompute
  18. 2026-08-05 17:30 UTCGHSA enrichment
  19. 2026-08-05 17:28 UTCNVD updateCVSS v4 → 2
  20. 2026-08-05 16:54 UTCEG score recompute
  21. 2026-08-05 16:54 UTCGHSA enrichment
  22. 2026-08-05 16:50 UTCMITRE cvelistV5CVSS v4 → 5.1
  23. 2026-08-05 01:19 UTCEG score recompute
  24. 2026-08-05 01:18 UTCNVD updateCVSS v4 → 2
  25. 2026-08-05 00:51 UTCEG score recompute
  26. 2026-08-05 00:50 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-18856?
CVE-2026-18856 is a medium vulnerability published on August 5, 2026. A vulnerability was determined in Poesis Rhymix CMS up to 2.1.33. This impacts the function procImporterAdminCheckXmlFile of the file modules/importer/importer.admin.controller.php of the component Data Import Module. This manipulation of the argument filename causes server-side request forgery.…
When was CVE-2026-18856 disclosed?
CVE-2026-18856 was first published in the National Vulnerability Database on August 5, 2026, with the most recent update on August 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18856 actively exploited?
CVE-2026-18856 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 86.3% of all scored CVEs.
What is the CVSS score of CVE-2026-18856?
CVE-2026-18856 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2026-18856?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18856, 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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