CVE-2019-17621

The UPnP endpoint URL /gena.cgi in the D-Link DIR-859 Wi-Fi router 1.05 and 1.06B01 Beta01 allows an Unauthenticated remote attacker to execute system commands as root, by sending a specially crafted HTTP SUBSCRIBE request to the UPnP service when connecting to the local network.

CVSS: 9.8Criticalscored by CISA
Exploited in the wild: Yes, in CISA KEV since 29 Jun 2023CISA deadline for US federal agencies: 20 Jul 2023public exploit code
EPSS: 90.6%chance of exploitation in the next 30 daystop 0.2% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 30 Dec 2019analysed here 12 Nov 2026

Do first. Apply updates per vendor instructions or discontinue use of the product if updates are unavailable. (CISA's required action for this KEV entry)

Summary

Triage

Attack surface: Server-side
Exploitable: At runtime
Attack vector: network
Weakness: CWE-78 OS Command Injection
Can a WAF block it?: Partly. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Products named in our analysis

dlink:dir-859_firmware
dlink:dir-822_firmware
dlink:dir-823_firmware
dlink:dir-865l_firmware
dlink:dir-868l_firmware
dlink:dir-869_firmware
dlink:dir-880l_firmware
dlink:dir-890l_firmware
dlink:dir-890r_firmware
dlink:dir-885l_firmware
dlink:dir-885r_firmware
dlink:dir-895l_firmware
dlink:dir-895r_firmware
dlink:dir-818lx_firmware

Fix and mitigation

WAF and other mitigations

Can a WAF block it? Partly. OS command injection puts shell syntax into the request. WAF rules catch common shell commands but miss encoded or unusual payloads.

Also consider: shlex/execve-style APIs

Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Listed since 29 Jun 2023.
CISA due date: 20 Jul 2023, the remediation deadline for US federal agencies
CISA required action: Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.
Public exploit code: Yes: 1 Metasploit module · 1 GitHub proof of concept
CISA SSVC: exploitation active, automatable yes, technical impact totalAssessed by CISA 4 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Metasploit

exploit/linux/upnp/dlink_dir859_subscribe_execexploit, rank excellent

GitHub proofs of concept

Squirre17/CVE-2019-176213 stars

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

30 Dec 2019Published
20 Jul 2022First public exploit or proof of concept932 days (about 3 years) later
29 Jun 2023Added to CISA KEV (exploited in the wild)344 days (about 11 months) later
20 Jul 2023CISA remediation due date (US federal agencies)21 days later
4 Feb 2025CISA SSVC assessment: exploitation active566 days (about 2 years) later
21 Oct 2025CVE record last updated259 days (about 9 months) later
12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Metric	Value	What it means
Attack vector	NetworkReachable over the internet or any routable network.	Reachable over the internet or any routable network.
Attack complexity	LowRepeatable attack, no special conditions.	Repeatable attack, no special conditions.
Privileges required	NoneThe attacker needs no prior access.	The attacker needs no prior access.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	HighTotal data disclosure possible.	Total data disclosure possible.
Integrity	HighComplete modification possible.	Complete modification possible.
Availability	HighFull outage possible.	Full outage possible.

Common questions

Is CVE-2019-17621 being exploited?

Yes. CVE-2019-17621 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2019-17621?

CVE-2019-17621 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2019-17621?

Yes. A fix has been recorded for CVE-2019-17621. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2019-17621 affect?

CVE-2019-17621 affects dlink:dir-859_firmware, dlink:dir-822_firmware, dlink:dir-823_firmware, dlink:dir-865l_firmware, and 10 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

8 references in the CVE record, grouped by the tags the record gives them.

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA KEV catalog: exploitation, date added, due date
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Metasploit Framework: exploit and scanner modules
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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