CVE-2023-53956

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2025-12-19. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.8Exploit: NoneExposed: 0

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

Flatnux 2021-03.25 contains an authenticated file upload vulnerability that allows administrative users to upload arbitrary PHP files through the file manager. Attackers with admin credentials can upload malicious PHP scripts to the web root directory, enabling remote code execution on the server.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track*)
EG Risk 56/100SSVC: 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
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
48.5%
KEV
Not listed

Published

December 19, 2025

Last Modified

April 15, 2026

Advisory Details (3)

Auto-updated May 21, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

Flatnux 2021-03.25 Authenticated File Upload Remote Code Execution | Advisories | VulnCheck

https://www.vulncheck.com/advisories/flatnux-authenticated-file-upload-remote-code-execution
generic🟡 PoC Available

flatnux 2021-03.25 - Remote Code Execution (Authenticated) - PHP webapps Exploit

https://www.exploit-db.com/exploits/51295
generic
http://flatnux.altervista.org/flatnux.html

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 43× 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.

Showing the most recent 100 of 117 total refreshes for this CVE.

  1. 2026-07-25 14:16 UTCEPSS rescore
  2. 2026-07-24 14:16 UTCEPSS rescore
  3. 2026-07-23 14:16 UTCEPSS rescore
  4. 2026-07-23 02:30 UTCEG score recompute
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  44. 2026-06-10 13:21 UTCEPSS rescore
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  47. 2026-06-07 15:24 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-53956?
CVE-2023-53956 is a high vulnerability published on December 19, 2025. Flatnux 2021-03.25 contains an authenticated file upload vulnerability that allows administrative users to upload arbitrary PHP files through the file manager. Attackers with admin credentials can upload malicious PHP scripts to the web root directory, enabling remote code execution on the server.
When was CVE-2023-53956 disclosed?
CVE-2023-53956 was first published in the National Vulnerability Database on December 19, 2025, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-53956 actively exploited?
CVE-2023-53956 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 48.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-53956?
CVE-2023-53956 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2023-53956?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-53956, 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.

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