CriticalCVE-2023-29300

    Adobe ColdFusion Deserialization of Untrusted Data Arbitrary code execution (CVE-2023-29300)

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

    What is affected, what to do

    This vulnerability allows for unauthenticated remote code execution (RCE) via deserialization of untrusted data in Adobe ColdFusion versions 2018u16 and earlier, 2021u6 and earlier, and 2023.0.0.330468 and earlier. An attacker can gain full control of the affected system without requiring user interaction. The vulnerability is actively exploited in ransomware campaigns since 2023 and is listed in the CISA KEV catalog. Organizations should urgently update to the latest version to mitigate this risk.

    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 lte *..2023.0.0.330468

    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

    99.99 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.99

    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
    257.02 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.

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    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.

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    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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    99.99 %
    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.

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    99.99
    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
    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

    CISA KEV flags this CVE as actively used in ransomware campaigns, and it sits among the CVEs most likely to be exploited at any given moment — public exploit chains (often paired with CVE-2023-26360) are integrated into commodity tooling. Attack preconditions are trivial: a network-reachable ColdFusion server, no authentication, no user interaction, direct RCE under the service account. For NIS2-regulated organisations with ColdFusion on the perimeter or in DMZ web stacks, this is a patch-now case at the highest urgency; internal-only instances remain critical because the deserialisation flaw is also used as a lateral-movement pivot after initial phishing access.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the Adobe patch now: ColdFusion 2018 Update 17, 2021 Update 7, or 2023 Update 1 (APSB23-40/APSB23-41). Any instance below these levels is considered exploitable — unauthenticated and without user interaction.
      • Pull internet-exposed ColdFusion servers (TCP 80/443, 8500, 8300) behind a reverse proxy/WAF or take them offline until the update is applied and verified.
      • Block external access to the CFIDE administrator paths (/CFIDE/administrator/, /CFIDE/adminapi/, /CFIDE/componentutils/) via WAF, reverse-proxy deny rule, or firewall ACL. These are the primary attack surface for the deserialisation chains.
      • Start a compromise assessment: scan the webroot and cfusion/wwwroot/CFIDE/ for unknown .cfm/.jsp files, webshells, and recently modified files (mtime since the first public PoC date). Pay particular attention to files with random names.
      • Rotate the ColdFusion service account and review its OS-level privileges; on RCE suspicion, isolate the host and take a forensic image before rebuilding.
      • Rotate any secrets reachable from the host: datasource credentials, API keys in neo-datasource.xml, session secrets, stored SMTP/LDAP credentials.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place ColdFusion hosts in a dedicated VLAN with egress restricted to an allowlist (database, SMTP, Adobe update endpoint only). No outbound connectivity to arbitrary internet IPs on 80/443/4444.
      • Enable WAF rules that block serialised Java objects in request bodies and query parameters (magic bytes aced 0005, Base64 rO0AB), plus patterns for known ColdFusion deserialisation gadgets (AnotherMonitor, com.sun.rowset.JdbcRowSetImpl).
      • Apply the Adobe Lockdown Guide: remove coldfusion.css, bind the administrator interface to localhost, disable Robust Exception Information, enable Sandbox Security.
      • JVM hardening: strip unused classloader paths from jvm.config, keep the Java runtime on a current patch level, and run ColdFusion as a least-privileged dedicated service user (never local admin/root).
      • Front with a reverse proxy (nginx, IIS ARR, Apache) that only forwards defined URI patterns to the application and limits /CFIDE/administrator/* to internal management networks.
      • Add an EDR rule for process spawns from coldfusion.exe/jrun.exe into cmd.exe, powershell.exe, wscript.exe, certutil.exe, rundll32.exe — not expected in normal CF operation.

    3. Runbook step 3

      Detection rules

      • Web access logs: POST requests to /CFIDE/adminapi/*, /CFIDE/componentutils/*, or /CFIDE/administrator/* from external IPs, especially with Content-Type: application/x-www-form-urlencoded and unusual payload sizes. KQL shape: W3CIISLog | where csUriStem startswith "/CFIDE/" and csMethod == "POST" and scStatus in (200,500).
      • Sysmon EID 1 / EDR: child processes of coldfusion.exe or jrun.exe (parent) spawning cmd.exe, powershell.exe, whoami, net.exe, certutil, curl, wget. Sigma: parent_image|endswith: '\coldfusion.exe' plus suspicious image.
      • File-integrity monitoring on wwwroot/CFIDE/ and cfusion/wwwroot/: new or modified .cfm, .jsp, .class files outside deployment windows — classic webshell drop-off.
      • Network/Zeek/Suricata: outbound connections from the ColdFusion host to unregistered download targets on 80/443/4444/8080 shortly after a suspicious POST. Enable the Suricata signatures covering CVE-2023-29300/-26360 (ET/Emerging Threats SIDs are published).
      • Windows Security log: logons by the ColdFusion service account from other hosts (EID 4624 type 3/10) or creation of new local users/groups (EID 4720/4732) shortly after a web anomaly.

    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 2018u16 (and earlier), 2021u6 (and earlier) and 2023.0.0.330468 (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
    • ≤ 2023.0.0.330468
    • —
    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-2023-29300Vendor advisory, Vendor advisory, pwn-watch
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2023-29300government-resource, Third-party advisory, US government resource
    • pwn.watchpwn.watch: Adobe ColdFusion: 2 actively exploited vulnerabilitiespwn-watch
    • helpx.adobe.comAdobe advisory: CVE-2023-38203pwn-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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