CriticalCVE-2023-38203

    Analysis CVE-2023-29300 Bypass: Adobe ColdFusion Pre-Auth RCE (CVE-2023-38203)

    Published In CISA KEV since Sources: pwn.watch, CVE.org

    What is affected, what to do

    Adobe ColdFusion versions 2018u17 (and earlier), 2021u7 (and earlier) and 2023u1 (and earlier) are affected by a Deserialization of Untrusted Data vulnerability that could result in Arbitrary code execution. Exploitation of this issue does not require user interaction.

    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
    • Adobe ColdFusion eq 2018..2018
    • Adobe ColdFusion eq 2021..2021
    • Adobe ColdFusion eq 2023..2023

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

    Metrics

    9.8

    Priority

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

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: pwn.watch, CVE.org

    97.1 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.89

    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
    256.92 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 exploited
    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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    9.8 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.

    Read in glossary
    9.8
    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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    97.1 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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.

    Read in glossary
    99.89
    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.

    Read in glossary
    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
    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 sits on KEV because it is network-reachable, requires no authentication, and lands code execution in the ColdFusion service context — a textbook initial-access vector that CISA confirms is used in ransomware campaigns. Exploitation likelihood is among the very highest in the entire CVE corpus, and public exploits plus Metasploit modules are readily available. Typical targets are internet-exposed legacy web applications in public administration, manufacturing, and financial services, often running outdated ColdFusion licences. Treat every externally reachable ColdFusion instance as a P1 incident candidate; internal instances rank one tier lower but still warrant patching within 72 h because of lateral-movement potential.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy Adobe security bulletin APSB23-40: ColdFusion 2018 Update 18, 2021 Update 8, or 2023 Update 2 (or newer). Prioritise any instance whose admin console or CFM endpoints are reachable from the internet.
      • Restrict access to the ColdFusion Administrator (/CFIDE/administrator, /CFIDE/adminapi) and Component Utilities (/CFIDE/componentutils) to management networks via reverse-proxy ACL or perimeter firewall. Default ports 8500/8501 and the production HTTPS port are in scope.
      • Launch a compromise assessment: review cfusion/logs (exception.log, application.log, server.log) and web-server access logs for the past 90 days for POST requests with serialised Java payloads, unexpected .jsp/.cfm files under /CFIDE/, and new scheduled tasks.
      • Rotate the ColdFusion service account (often SYSTEM or root) and reset every datasource credential stored in neo4j and the Password Manager, plus the ColdFusion admin password hash.
      • If patching cannot happen immediately, place the instance behind a WAF or take it off-net — unauthenticated deserialisation RCE is actively weaponised and in use as a ransomware entry vector.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: move ColdFusion hosts into a dedicated back-end VLAN; egress-filter outbound traffic to unknown IPs on TCP 4444/8080/443 and to pastebin, interact.sh and cloud-storage domains to break second-stage loaders.
      • WAF / reverse-proxy rules: block POST requests to /CFIDE/* carrying base64-encoded Java serialisation magic (rO0AB), Content-Type application/x-java-serialized-object, or oversized bodies (>8 KB); at minimum force alert mode.
      • Endpoint hardening: apply Adobe's Lockdown Guide for the installed ColdFusion version — in particular disable unused CFCs, remove the /CFIDE/scripts mapping, and enable Secure Profile defaults.
      • IAM / least-privilege: migrate the ColdFusion service to a dedicated low-privilege account; strip write permissions on the webroot, cfusion/wwwroot, and startup directories; use AppLocker or SELinux profiles to prevent cmd.exe or powershell.exe spawning as a child of the JVM.
      • Configuration: disable Robust Exception Information in the Administrator so stack traces do not leak back to the attacker; switch session management to J2EE sessions with Secure/HttpOnly cookies.
      • Backup readiness: verify offline snapshots of ColdFusion configuration and backing databases — with confirmed ransomware tradecraft, recoverability is the last line of defence.

    3. Runbook step 3

      Detection rules

      • Web access logs: POSTs to /CFIDE/adminapi/, /CFIDE/administrator/, /CFIDE/componentutils/ from external IPs returning HTTP 200/500 — Sigma shape: selection.cs-uri-stem|startswith: '/CFIDE/' AND selection.cs-method: 'POST' AND selection.c-ip|not_internal.
      • Sysmon EID 1 / EDR process ancestry: coldfusion.exe, jrun.exe, or java.exe (with a ColdFusion classpath) spawning cmd.exe, powershell.exe, certutil.exe, bitsadmin.exe, or wmic.exe — high-confidence indicator of successful deserialisation RCE.
      • Sysmon EID 11 / auditd: creation of .jsp, .cfm, .cfml, or .class files under cfusion/wwwroot/CFIDE/, cfusion/wwwroot/CFIDE/scripts/, or cfusion/runtime/work/ outside planned deployment windows.
      • Network telemetry (Zeek/Suricata): outbound connections from the JVM process to non-RFC1918 destinations within 60 s of a /CFIDE/ POST — strong correlation with reverse shells or loader downloads.
      • KQL example for Microsoft Defender: DeviceProcessEvents | where InitiatingProcessFileName in~ ('coldfusion.exe','jrun.exe','java.exe') | where FileName in~ ('cmd.exe','powershell.exe','whoami.exe','net.exe','rundll32.exe').

    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

    Adobe ColdFusion versions 2018u17 (and earlier), 2021u7 (and earlier) and 2023u1 (and earlier) are affected by a Deserialization of Untrusted Data vulnerability that could result in Arbitrary code execution. Exploitation of this issue does not require user interaction.

    Source: pwn.watch, NVD (NIST), cvelistv5, CISA KEV Catalog, 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
    AdobeColdFusion
    • —
    • —
    adobecoldfusion
    • 2018
    • 2021
    • 2023
    • —
    • —
    • —

    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

    • helpx.adobe.comAdobe advisory: CVE-2023-38203Vendor advisory, Patch, Vendor advisory, pwn-watch
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2023-38203government-resource, Third-party advisory, US government resource
    • pwn.watchpwn.watch: Adobe ColdFusion: 2 actively exploited vulnerabilitiespwn-watch
    • helpx.adobe.comAdobe advisory: CVE-2023-29300pwn-watch
    • NVD (NIST)NVD: CVE-2023-29300pwn-watch
    • NVD (NIST)NVD: CVE-2023-38203pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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