CriticalCVE-2021-36260

    Hikvision Improper Input Validation (CVE-2021-36260)

    Published In CISA KEV since Sources: CVE.org

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    What is affected, what to do

    A command injection vulnerability in the web server of some Hikvision product. Due to the insufficient input validation, attacker can exploit the vulnerability to launch a command injection attack by sending some messages with malicious commands.

    The vulnerability is being actively exploited; treat it as a priority. 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
    • Hikvision Ds-7608ni-k1\/8p\/4g Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7616ni-k1 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7604ni-q1 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7604ni-q1\/4p Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7608ni-q1 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7608ni-q1\/8p Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7608ni-q2 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7608ni-q2\/8p Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7616ni-q1 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7616ni-q2 Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7616ni-q2\/16p Firmware lte 4.30.210..4.31.000
    • Hikvision Ds-7104ni-q1 Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7104ni-q1\/4p Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7104ni-q1\/4p\/m Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7104ni-q1\/m Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7108ni-q1 Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7108ni-q1\/8p Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7108ni-q1\/8p\/m Firmware lte 4.30.300..4.31.100
    • Hikvision Ds-7108ni-q1\/m Firmware lte 4.30.300..4.31.100

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    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: CVE.org

    99.87 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.96

    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
    228.94 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.

    Read in glossary
    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“.

    Read in glossary
    99.87 %
    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
    99.96
    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
    CISA assessment (SSVC)
    Exploitation: active · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 6 February 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-78

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable without authentication or user interaction, needs a single HTTP request, and yields command execution as root — public exploit code and scanner modules have been widespread for years, and exploitation likelihood is among the highest of any CVE. In the wild it is primarily mass-exploited by IoT botnets to build DDoS capacity and proxy networks and to gain a foothold inside internal networks; CISA does not flag known ransomware use. Treat any internet-exposed camera as critical and presumed compromised; internally segmented devices without egress carry lower but still high priority because of their pivot potential into OT/KRITIS environments.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Kill internet exposure now: Block all Hikvision cameras and NVRs with an internet-reachable web interface (typically TCP 80/443, plus SDK port 8000 and RTSP 554) at the perimeter firewall and remove UPnP/port-forwarding rules on edge routers. Scan your own public ranges (or check Shodan/Censys) for Hikvision banners.
      • Update firmware: For every affected model (including DS-2CD2021G1-I(W), DS-2CD2023G2-I(U), DS-2CD2026G2-IU/SL, DS-2CD2027G2-L(U), DS-2CD2043G2-I(U), DS-2CD2046G2-IU/SL, DS-2CD2047G2-L(U)), install the fixed firmware — patch available from the vendor; look up the exact version in Hikvision's security advisory for CVE-2021-36260. Only use firmware from official Hikvision sources.
      • Include OEM devices: Check the asset inventory for rebranded Hikvision OEM cameras running Hikvision firmware; banners, web UI and /SDK/ paths reveal their origin.
      • Assume compromise if exposed: Devices that were internet-reachable before patching should be factory-reset, reflashed and reconfigured after the update — IoT botnets commonly drop persistent implants on writable partitions.
      • Rotate credentials: Reset admin and ONVIF/RTSP accounts on all affected devices and any credentials for these cameras stored in the VMS/NVR; no reuse across devices.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: Move video surveillance into a dedicated VLAN/zone (IEC 62443 zone model); only NVR/VMS servers may reach cameras on 80/443/554/8000. Deny all outbound internet traffic from the camera VLAN (default-deny egress) to stop payload downloads and C2.
      • Administrative access: Restrict the web UI to a jump host or management network; remote access only via VPN with MFA, never via port forwarding. Disable Hik-Connect/P2P cloud services unless strictly required.
      • IPS/WAF rule: In front of exposed devices or at the zone boundary, block HTTP PUT requests to /SDK/webLanguage, especially where the XML body contains shell metacharacters ($(, backticks, ;, |) inside <language>. Enable available Suricata/ET signatures for CVE-2021-36260 in blocking mode.
      • Device hardening: Disable unused services (Telnet/SSH, UPnP, SNMPv1/v2c, unused ports); enforce HTTPS; configure the on-device IP filter (allowlist) to NVR/management IPs only.
      • Lifecycle management: Identify end-of-life models without a firmware fix and replace them, or isolate strictly until replacement; KRITIS operators should record the supply-chain risk in the ISMS.

    3. Runbook step 3

      Detection rules

      • Web/proxy logs or Zeek http.log: Requests with method=PUT and uri=/SDK/webLanguage, particularly with bodies containing $( or commands such as wget, curl, tftp, busybox, echo. SPL sketch: index=netproxy http_method=PUT uri_path="/SDK/webLanguage" | stats count by src_ip, dest_ip.
      • Suricata/IDS alerts: Correlate ET EXPLOIT signatures for Hikvision command injection (CVE-2021-36260) on camera segments; any hit from an external source is an incident.
      • Outbound traffic from the camera VLAN: Watch firewall/NetFlow for connections from camera IPs to internet destinations (HTTP downloads, TFTP 69/udp, IRC-like or unusual high ports). KQL sketch: CommonSecurityLog | where SourceIP in (camera_ips) and DestinationIP !in (nvr_ips) and DeviceAction == "allow".
      • Lateral movement/scanning: Cameras performing port scans (e.g. on 23, 80, 8000) or SSH/Telnet brute force against other hosts — classic botnet propagation; analyse Zeek conn.log for high fan-out per camera IP.
      • Device state: Unexpected configuration changes, new user accounts, reboots or changed firmware builds in the VMS/NVR event log or camera syslog.

    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

    A command injection vulnerability in the web server of some Hikvision product. Due to the insufficient input validation, attacker can exploit the vulnerability to launch a command injection attack by sending some messages with malicious commands.

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

    Vendors and products

    Affected operating systems

    Affected operating systems
    Otherhikvisionds-2cd2021g1-i\(w\)_firmware—
    Otherhikvisionds-2cd2023g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2026g2-iu\/sl_firmware—
    Otherhikvisionds-2cd2027g2-l\(u\)_firmware—
    Otherhikvisionds-2cd2027g2-lu\/sl_firmware—
    Otherhikvisionds-2cd2043g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2046g2-iu\/sl_firmware—
    Otherhikvisionds-2cd2047g2-l\(u\)_firmware—
    Otherhikvisionds-2cd2063g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2066g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2066g2-iu\/sl_firmware—
    Otherhikvisionds-2cd2083g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2086g2-i\(u\)_firmware—
    Otherhikvisionds-2cd2086g2-iu\/sl_firmware—
    Otherhikvisionds-2cd2087g2-l\(u\)_firmware—
    Otherhikvisionds-2cd2121g0-i\(w\)\(s\)_firmware—
    Otherhikvisionds-2cd2121g1-i\(w\)_firmware—
    Otherhikvisionds-2cd2121g1-idw_firmware—
    Otherhikvisionds-2cd2121g1_firmware—
    Otherhikvisionds-2cd2123g2-i\(s\)_firmware—
    Otherhikvisionds-2cd2123g2-iu_firmware—
    Otherhikvisionds-2cd2127g2-\(-su\)_firmware—
    Otherhikvisionds-2cd2143g2-i\(s\)_firmware—
    Otherhikvisionds-2cd2143g2-iu_firmware—

    Weakness classes (CWE)

    • CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

      Base

      The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

      Entry at MITRE CWE-78

    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
    Packet StormHikvision Web Server Build 210702 Command Injection (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormHikvision IP Camera Unauthenticated Command Injection (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)HIKRAVEN (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)HikvisionExploiter_fixed (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • hikvision.comen/support/cybersecurity/security-advisory/security-notificatio…x_refsource_MISC, Vendor advisory
    • packetstormsecurity.comfiles/164603/Hikvision-Web-Server-Build-210702-Command-Injectio…x_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • packetstormsecurity.comfiles/166167/Hikvision-IP-Camera-Unauthenticated-Command-Inject…x_refsource_MISC, Exploit, Third-party advisory, Vulnerability database
    • cyfirma.comwp-content/uploads/2022/08/HikvisionSurveillanceCamerasVulnerab…x_refsource_MISC, Broken link, Exploit, Third-party advisory
    • therecord.mediaexperts-warn-of-widespread-exploitation-involving-hikvision-cam…x_refsource_MISC, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36260government-resource, US government resource
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