CriticalCVE-2025-42999

    Insecure Deserialization in SAP NetWeaver (Visual Composer development server) (CVE-2025-42999)

    Published Last modified In CISA KEV since Sources: pwn.watch, CVE.org, SAP Note

    What is affected, what to do

    This vulnerability allows a privileged attacker to compromise the confidentiality, integrity, and availability of the host system by deserializing untrusted or malicious content. The attack requires user privileges to upload content and is actively exploited in ransomware campaigns. Affected products include SAP NetWeaver, specifically the Visual Composer Metadata Uploader. It is crucial to apply a patch as soon as it becomes available to mitigate this vulnerability. The vulnerability is listed in the CISA KEV catalog, highlighting its significance.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • SAP NetWeaver (Visual Composer development server) eq VCFRAMEWORK 7.50..VCFRAMEWORK 7.50

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    9.1

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    9.1

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: pwn.watch, CVE.org, SAP Note

    12.9 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 96.3

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    253.63 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

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    9.1 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

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    9.1
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    12.9 %
    Elevated — model estimates 10-50% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

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    96.3
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

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    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 12 May 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-502

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE is on CISA KEV and carries the ransomware-use flag — it is actively being chained with CVE-2025-31324 as the entry point to fully compromise internet-exposed SAP NetWeaver estates, including webshell deployment and follow-on encryption. The CVSS vector (network-reachable, low complexity, scope change, full CIA impact) combined with a very high exploitation likelihood makes every externally reachable NetWeaver AS Java with active Visual Composer a top-priority patch target (24-72 h). Internal, segmented SAP systems are second tier but should not be deferred, since the privileged-user prerequisite is realistically met via stolen admin credentials or lateral movement from a compromised SAP GUI client. Rank remediation by: (1) internet exposure, (2) VCFRAMEWORK active, (3) processing of regulated data within NIS2 / GDPR / KRITIS scope.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Apply the SAP Security Note for CVE-2025-42999 (May 2025 Patch Day, shipped alongside CVE-2025-31324 for the Visual Composer Metadata Uploader). Affected scope is SAP NetWeaver AS Java with the Visual Composer component (VCFRAMEWORK) deployed. Confirm the required patch level in the SAP ONE Support Launchpad note.
      • Immediately restrict external reachability of Visual Composer endpoints: /developmentserver/metadatauploader, /irj/*, paths under /webdynpro/. Configure the SAP Web Dispatcher, reverse proxy, or WAF so that metadatauploader is reachable only from defined administrative source networks.
      • Determine whether VCFRAMEWORK is actually in use. If not, decommission Visual Composer following the SAP note procedure — avoids recurring patch exposure.
      • Run a compromise assessment before patching: scan j2ee/cluster/apps/sap.com~tc~lm~webadmin~mainframe~wd/servlet_jsp/webdynpro/... and the global irj work directories for foreign .jsp, .class, or .jar artefacts, including helper.jsp, cache.jsp, and random 8-character filenames. This CVE is being chained with CVE-2025-31324 to drop webshells.
      • Rotate SAP Java stack service accounts (SAPService, j2ee_admin) and any trust material issued by AS Java (RFC destinations, Secure Store keys) if indicators are positive.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: isolate AS Java from the internet. Block external exposure of ports 50000/50001 (default HTTP/HTTPS) and any Web-Dispatcher-mapped /developmentserver/* or /irj/servlet_jsp/irj/root/* paths.
      • WAF rule: block or restrict HTTP POST/PUT to /developmentserver/metadatauploader* to known admin source IPs. Drop multipart uploads carrying serialised Java objects (magic bytes AC ED 00 05) and raw application/octet-stream payloads on these paths.
      • IAM hardening: trim membership of SAP_J2EE_ADMIN, Administrators, NWA_SUPERADMIN to the strict minimum, enforce MFA / jump-host policy for UME admin logins. The CVE requires a privileged user — every extra admin account widens the attack surface.
      • Filesystem hardening: constrain write access of the <sid>adm user to webroot directories via OS ACL. Apply AppArmor/SELinux profiles or Windows ACLs that render j2ee/cluster/apps/* read-only where deployment flow allows it.
      • Egress control: allow-list outbound traffic from the SAP host (SAP support, update servers only). Block arbitrary internet destinations, particularly 4444/tcp or 443/tcp to unlisted hosts, to defeat reverse shells launched from deserialisation payloads.
      • Monitoring baseline: switch SAP Security Audit Log to level "All" for admin users and enable Read Access Logging for Visual Composer services.

    3. Runbook step 3

      Detection rules

      • Web access log (ICM / Web Dispatcher): HTTP requests to /developmentserver/metadatauploader with 200/201 response and POST/PUT method. Sigma shape: selection: cs-uri-stem|contains: "/developmentserver/metadatauploader" AND cs-method in ["POST","PUT"]. Any hit outside planned admin activity is in-scope for triage.
      • File creation in web directories: Sysmon EID 11 or auditd -w /usr/sap/<SID>/J00/j2ee/cluster/apps -p wa for new .jsp, .jspx, or .class files owned by <sid>adm. KQL example: DeviceFileEvents | where FolderPath has "j2ee/cluster/apps" and FileName endswith ".jsp".
      • Process ancestry: child processes of jlaunch.exe / jstart or java (SAP J2EE) spawning cmd.exe, powershell.exe, /bin/sh, curl, wget, nc. Sysmon EID 1 or EDR equivalent. AS Java deserialisation exploitation lands in exactly this chain.
      • SAP Security Audit Log: events AU5/AUE (RFC/service calls by admin users outside change windows), DU9 (admin download), and new SDM / Deploy Controller deployments without a matching change ticket.
      • Network telemetry (Zeek/Suricata): outbound TCP from SAP hosts to destinations not registered in the CMDB; HTTP egress with User-Agent Java/* originating from AS Java hosts.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    SAP NetWeaver Visual Composer Metadata Uploader is vulnerable when a privileged user can upload untrusted or malicious content which, when deserialized, could potentially lead to a compromise of confidentiality, integrity, and availability of the host system.

    Source: pwn.watch, CISA KEV Catalog, sap_note, cvelistv5, NVD (NIST), CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    SAP_SESAP NetWeaver (Visual Composer development server)
    • VCFRAMEWORK 7.50
    • —
    sapnetweaver
    • 7.5
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-502Deserialization of Untrusted Data

      Base

      The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

      Entry at MITRE CWE-502

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • me.sap.comSAP advisory: SAP NetWeaverpwn-watch
    • url.sapsapsecuritypatchday
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-42999government-resource
    • onapsis.comblog/active-exploitation-of-sap-vulnerability-cve-2025-31324
    • pwn.watchpwn.watch: SAP NetWeaver: NetWeaver Deserialization Vulnerabilitypwn-watch
    • NVD (NIST)NVD: CVE-2025-42999pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: active, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentchanged
      {"id":"CVE-2025-42999","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2025-05-17T03:55:58.995900Z"}
      {"id":"CVE-2025-42999","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2025-05-12T00:00:00+00:00"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

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