Administrative command execution via zero-length TDDP payload
Published Jan 21, 2026 · Updated Jan 21, 2026
Authentication bypass in TP-Link Archer C20 v5/v6, Archer AX53 v1, and TL-WR841N v13 allows remote attackers to run admin commands. In tddp_parserHandler(), a zero pktLength skips DES decryption, yet post-header bytes enter the decrypted-data buffer and execute as trusted subcommands. Access to UDP port 1040 on the local network is sufficient; factory reset erases configuration, and repeated reboot commands interrupt service.
Summary
What happened
Authentication bypass in TP-Link Archer C20 v5/v6, Archer AX53 v1, and TL-WR841N v13 allows remote attackers to run admin commands. In tddp_parserHandler(), a zero pktLength skips DES decryption, yet post-header bytes enter the decrypted-data buffer and execute as trusted subcommands. Access to UDP port 1040 on the local network is sufficient; factory reset erases configuration, and repeated reboot commands interrupt service.
The record
- CVE
- CVE-2026-0834
- Published
- Jan 21, 2026
- Updated
- Jan 21, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-290, CAPEC-88, T1210
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 21, 2026CVE publishedPublication date reported by the CVE source.
- Jan 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- mattgsys TDDP authentication-bypass proof of conceptfunctional · validated
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Technologies
Your stack
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Your stack
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