What is CVE-2026-11405?
The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8. - The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key). - After normal authentication fails, it calls GetValue("sys.rzadmin.password") to read a backdoor password from the device configuration. - It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password. A successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked — any username works with the backdoor
Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 96 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 0.7% probability of exploitation in the next 30 days, higher than 54.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 9.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-07-06, last modified 2026-07-08
Is CVE-2026-11405 being exploited?
Weaponised exploit code for CVE-2026-11405 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 33 in the Threadlinqs vulnerability feed.
- HORKimhab/CVE-2026-11405 (github)
Affected products and versions
- Tenda: firmware
How to fix CVE-2026-11405
No vendor patch reference has been recorded for CVE-2026-11405 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-11405
1 tracked threat in the Threadlinqs corpus references CVE-2026-11405, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .