Vulnerability report

Trusted Third Party Report High Confidence Not in CISA KEV

CVE-2023-54398

Yonyou U8 Cloud Java Deserialization RCE

Yonyou / U8 Cloud · 1.0

Watch CVE-2023-54398 Browse KEV feed
Severity
CVSS 9.3 · Critical
Confidence
High
Exploit status
Trusted Third Party Report
EPSS
1.2%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-54398 is an unauthenticated vulnerability affecting Yonyou U8 Cloud.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Also reported by third-party sources. Confidence is high.

Who is affected?

Yonyou / U8 Cloud, including 1.0, 2.0, and 2.1.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Yonyou U8 Cloud Java Deserialization RCE

Yonyou U8 Cloud contains an unauthenticated Java deserialization vulnerability in the nc.impl.pub.filesystem.FileManageServlet component that allows remote unauthenticated attackers to execute arbitrary OS commands by sending a serialized payload via POST request. Attackers can exploit the doAction method, which passes raw HTTP request body data directly to ObjectInputStream.readObject() without filtering, to achieve remote code execution.

Exploitation evidence was first observed by the Shadowserver Foundation on 2025-02-13.

Yonyou Affected
U8 Cloud
1.0 2.0 2.1 2.3 2.5 2.6 2.65 2.7 3.0 3.1 3.2 3.5 3.6 3.6sp
View vendor advisory (opens in new tab)
Published
15 Sep 2026
Exploitation Attempts Reported
15 Sep 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2023-54398
  • Vendor Advisory security.yonyou.com · Vendor Advisory https://security.yonyou.com/#/noticeInfo?id=400
  • AVD Advisory avd.aliyun.com · Third-Party Advisory https://avd.aliyun.com/detail?id=AVD-2023-1686894
  • Third-Party Advisory — vulncheck.com vulncheck.com · Third-Party Advisory https://www.vulncheck.com/advisories/yonyou-u8-cloud-java-deserializa...
  • CN-SEC Blog cn-sec.com · Exploit https://cn-sec.com/archives/2182384.html
  • CSDN Blog blog.csdn.net · Exploit https://blog.csdn.net/qq_41904294/article/details/134277353
  • Vendor Homepage yonyou.com · Product https://www.yonyou.com/Global/

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

CVE

Recorded 15 Sep 2026

A trusted third party reported exploitation attempts.

Proof of concept available

CVE

Recorded 15 Sep 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-09-15 17:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.3 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS

1.2%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Deserialization of Untrusted Data CWE-502

All CVSS Scores

CVSS v4.0 9.3 Critical

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

CSDN Blog

cve · Created Unknown

CN-SEC Blog

cve · Created Unknown

Timeline

From disclosure to observed exploitation attempts

  1. 17:00 UTC

    Public PoC available

    Public proof-of-concept code published

  2. 17:00 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party report of exploitation attempts

  3. 16:43 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 16:26 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-54398

Sample API response 
{
  "cve_id": "CVE-2023-54398",
  "confidence": "High",
  "cvss_score": 9.3,
  "cvss_estimated": false,
  "epss_score": 0.012,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}