CVE-2025-29635: D-Link DIR-823X authenticated command injection on an end-of-life router

Quick Answer

CISA added CVE-2025-29635 to its Known Exploited Vulnerabilities catalog on 2026-04-24, confirming that exploitation has occurred. If you operate D-Link DIR-823X, identify the exact version and relevant configuration now, preserve security evidence, and follow the live vendor remediation. A KEV match does not prove your system was compromised, and installing an update does not rule out earlier exploitation.

Last verified: 2026-09-17 UTC. CISA KEV snapshot version 2026.09.16. Recheck the live advisory before changing production.

Context

Status At A Glance

Product scope	D-Link — DIR-823X
CVE	CVE-2025-29635
TechGeeks response tier	P0 — confirm an exact match and act now
CISA KEV added	2026-04-24
Vendor severity	Consult the live vendor advisory; no vendor severity is inferred from KEV status.
CVSS	Consult the live vendor advisory; no CVSS value is inferred from KEV status.
Ransomware field	Unknown — this is not the same as No; CISA has not marked the field Known.
Forensic-triage field	No in the current CISA field; organizations should still investigate when exposure or evidence warrants it.
CWE	CWE-77
Federal remediation date	2026-05-08 — applies to covered federal agencies; other organizations should set a risk-based deadline.

What Happened

D-Link DIR-823X Command Injection Vulnerability. D-Link DIR-823X contains a command injection vulnerability that allows an authorized attacker to execute arbitrary commands on remote devices by sending a POST request to /goform/set_prohibiting via the corresponding function. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization. CISA's KEV listing confirms exploitation evidence, but it does not state how widespread the activity is or prove that any particular installation was compromised.

Affected Scope

D-Link DIR-823X contains a command injection vulnerability that allows an authorized attacker to execute arbitrary commands on remote devices by sending a POST request to /goform/set_prohibiting via the corresponding function. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.

Match the exact edition, hardware or virtual platform, release, patch level, enabled feature, and management exposure. A product-family name alone is not enough to establish applicability.

Steps

What To Do Now

1. Confirm. Inventory every DIR-823X asset and record its exact version, patch level, role, relevant configuration, and exposure.
2. Preserve. Save UTC timestamps, off-device authentication, firewall, proxy, DNS, endpoint, application, and SIEM evidence before logs rotate or a disruptive change removes context.
3. Contain. Restrict unnecessary internet and management-plane access using supported controls. Follow the live advisory: Open the live D-Link advisory.
4. Remediate. D-Link identifies the affected model as end of life/end of service; retire and replace it rather than relying on continued exposure.
5. Validate. Verify the resulting version or patch level, service health, logging, expected access, an expected denial, and representative dependent workflows.
6. Escalate. If exposure overlapped the vulnerable period or evidence is suspicious, treat the system as a potential incident and follow vendor and incident-response recovery guidance.

Fixed Releases And Mitigation

Verified fixed release, patch level, or update guidance captured at the last check:

A fixed build or KB was not safely preserved in the research record. Check the live vendor advisory before production changes; do not infer a fixed version from this summary.

Mitigation boundary: Discontinue use and replace the affected end-of-life product, following D-Link SAP10469.

A workaround, access restriction, or provider-side control reduces a described path; it does not necessarily remove vulnerable code or erase compromise.

Investigation And Recovery

CISA's KEV record does not mark this entry for forensic triage. That field is not proof of a clean system; consult the vendor advisory for indicators and recovery guidance.

When an attacker may have gained administrative, root, SYSTEM, identity, management-plane, or code-execution access, patching alone is not an eradication claim. Preserve evidence, scope affected accounts and downstream systems, rotate exposed credentials or certificates when justified, and rebuild from a trusted source when vendor or incident-response guidance requires it.

Notes

Exploitation Evidence

Vendor statement: The D-Link advisory does not safely provide a vendor exploitation statement in the local source; CISA added the CVE to KEV on 2026-04-24.

CISA statement: CVE-2025-29635 was added to KEV on 2026-04-24. The ransomware field is Unknown, and the forensic-triage field is No. These are separate signals.

Validation And Boundaries

This notice does not prove that every product carrying the family name is affected, that exploitation is widespread, that a clean indicator search rules out compromise, or that a successful update restored trust. TechGeeks has not reproduced the exploit and does not replace the vendor advisory, asset inventory, vulnerability scanner, or incident-response process.

Related TechGeeks Resources

• Security Hot Page
• All Security Notices
• What to Do When a Device Hits CISA KEV
• Router CVE Exposure, Version, and Mitigation Checklist
• IoT Firmware Update and End-of-Support Checklist
• Live Protect and Runtime Vulnerability Shielding

References

• D-Link advisory or support notice
• NVD CVE record
• CISA source

Wrap-Up

Record whether CVE-2025-29635 applies to your environment. If it does, assign an owner, preserve the change and investigation evidence, complete the vendor action, and document the validated result.

Correction policy: If a primary source changes affected versions, remediation, exploitation status, or recovery guidance, TechGeeks will update this page and its verification date.