CVE-2019-17621 — D-Link DIR-859 Router Command Execution Vulnerability

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — supportannouncement.us.dlink.com (NIST National Vulnerability Database)
• Documented patch — supportannouncement.us.dlink.com (NIST National Vulnerability Database)

CISA required action CISA

Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.

US federal deadline: Jul 20, 2023 — passed 1183 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Dlink Dir-818lx Firmware, Dlink Dir-822 Firmware, Dlink Dir-823 Firmware…).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
4. Apply the fixed version or the patch documented under Remediation.
5. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
6. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-78 · OS Command Injection

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 89.62%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Look for parameters with command/query metacharacters and unexpected child processes of the service.
• Hunt retroactively in logs from before Jun 29, 2023 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• Affected products added · dlink/dir-859 firmware, dlink/dir-822 firmware, dlink/dir-823 firmware, dlink/dir-865l firmware, dlink/dir-868l firmware
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · Published → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Record published
  Oct 13, 2026
• CVSS changed · 9.8
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Source status changed · → Published
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• 2023
• Added to CISA KEV catalog
  Jun 28, 2023 · CISA
• 2019
• CVE published
  Dec 30, 2019 · mitre

Source activity

Repeated readings are counted rather than listed.

• 3× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

12 on the record

• www.dlink.com/en/security-bulletin
  x_refsource_MISC, Vendor Advisory, CVE Program (cve.org) e CISA ADP
• supportannouncement.us.dlink.com/announcement/publication.aspx
  x_refsource_CONFIRM, Patch, Vendor Advisory, CVE Program (cve.org) e CISA ADP
• supportannouncement.us.dlink.com/announcement/publication.aspx
  x_refsource_CONFIRM, Patch, Vendor Advisory, CVE Program (cve.org) e CISA ADP
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• medium.com/%40s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-es-fad716
  x_refsource_MISC, Broken Link, CVE Program (cve.org) e CISA ADP
• medium.com/@s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-en-d94b47a1
  GitHub Security Advisories
• packetstormsecurity.com/files/156054/D-Link-DIR-859-Unauthenticated-Remote-Command-Execution.
  x_refsource_MISC, Exploit, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• medium.com/%40s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-en-d94b47
  x_refsource_MISC, Exploit, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• nvd.nist.gov/vuln/detail/CVE-2019-17621
  GitHub Security Advisories
• medium.com/@s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-es-fad71662
  GitHub Security Advisories
• www.ftc.gov/system/files/documents/cases/dlink_proposed_order_and_judgment_7-2-19
  x_refsource_MISC, Third Party Advisory, US Government Resource, CVE Program (cve.org) e CISA ADP
• github.com/advisories/GHSA-4cjx-47hq-7hc2
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-7067 D-Link DIR-822 udhcpd DHCP Service dhcpd.c system command injection Apr 26, 2026
• Critical CVE-2026-3485 D-Link DIR-868L SSDP Service sub_1BF84 os command injection Mar 3, 2026
• High CVE-2025-63932 OS Command Injection in Dlink Dir-868l Firmware Nov 19, 2025
• Critical CVE-2024-0769 D-Link DIR-859 Router Path Traversal Vulnerability KEV Jan 21, 2024
• Critical CVE-2018-6530 D-Link Multiple Routers OS Command Injection Vulnerability KEV Mar 6, 2018

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2019-17621 is "D-Link DIR-859 Router Command Execution Vulnerability", rated Critical. It affects Dir-818lx Firmware (Dlink); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 89.62% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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