NVD / CVE Program· CNA securin

CVE-2026-42373: D-Link DIR-605L B2 Hardcoded Telnet Backdoor Credentials

Noroxi assessment

Priority: Monitor (action score 35/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.47% (FIRST EPSS).
Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

D-Link DIR-605L Hardware Revision B2 (End-of-Life, EOL) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /bin/telnetd.sh with the username "Alphanetworks" and the static password "wrgn76_dlwbr_dir605L" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a -u user:password flag, and the custom login binary uses strcmp() to validate credentials. Successful authentication grants an unauthenticated attacker on the local network a root shell with full administrative control. The device has reached End-of-Life (EOL) and will not receive patches.

HighCVSS 8.8 · v3.1—No exploit No fix recorded

BDU:2026-06320

Published: May 4, 2026
Updated: Oct 25, 2026
EPSS: 0.4% · 40th percentile
CWE: CWE-798

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 8.8
CNA · securin: 9.8; 1.0 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
dlink	dir-605l firmware	cpe:2.3:o:dlink:dir-605l_firmware
dlink	dir-605l	cpe:2.3:h:dlink:dir-605l

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

dlink dir-605l firmwareall versions

Versions reported by the vendor

Affected version ranges reported by the assigning authority (securin). Independent of NVD's CPE analysis and usually ahead of it.

D-Link DIR-605L Firmware
- B2affected

Same product

dlink: all records

Other highest-scoring records for the same primary product.

CVE-2021-40655An informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT.KEV
86Now
CVE-2012-10021D-Link DIR-605L Captcha Handling Buffer Overflow
60This week
CVE-2025-4443D-Link DIR-605L sub_454F2C command injection
40Plan

Published before and after this one in the same product

← EarlierCVE-2026-5983Apr 9, 2026 · D-Link DIR-605L POST Request formSetDDNS buffer overflow
29Monitor
← EarlierCVE-2026-5984Apr 9, 2026 · D-Link DIR-605L POST Request formSetLog buffer overflow
29Monitor
← EarlierCVE-2026-42372May 4, 2026 · D-Link DIR-605L A1 Hardcoded Telnet Backdoor Credentials
35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Arjun BasnetSecurinfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-423720 days apartD-Link DIR-605L A1 Hardcoded Telnet Backdoor Credentials
35Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0161 · May 5, 2026(D Link Çoklu Ürün Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Someone on the same network segment can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Adjacent
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-798 · Use of Hard-coded Credentials

CVSS vector

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

nvd-primary

Root cause

For convenience in support or manufacturing, an account that is identical on every device is embedded in the software. Credentials learned from one device work on all of them.

The bug in code

The whole CWE-798 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const SUPPORT_USER = "support";
2const SUPPORT_PASS = "hardcoded-password";

Fixed

1const creds = await provisioning.deviceCredentials(deviceId);
2if (creds.mustRotate) await forcePasswordChange(deviceId);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

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