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CVE-2021-29441 is an authentication bypass vulnerability in Alibaba Nacos, a platform for dynamic service discovery, configuration management, and service management. In Nacos versions prior to 1.4.1, when built-in authentication is enabled, requests are filtered by the AuthFilter servlet filter. The vulnerable implementation contains a trust mechanism intended for Nacos server-to-server requests that can be triggered based on the HTTP User-Agent header. Because this header is client-controlled and can be trivially spoofed, an unauthenticated remote attacker can cause the filter to treat arbitrary requests as trusted internal traffic and skip authentication checks. Successful exploitation can expose administrative functionality and permit unauthorized creation or use of privileged accounts within the Nacos management plane.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a small standalone Python proof-of-concept/operational exploit for CVE-2021-29441, an authentication bypass in Alibaba Nacos before 1.4.1. The repo contains only two files: a README describing the vulnerability and exploit conditions, and a single executable script, exploit.py, which is the main entry point. The exploit works by creating a requests.Session and hardcoding the spoofed header 'User-Agent: Nacos-Server', which the vulnerable Nacos AuthFilter incorrectly trusts as an internal request marker. Using that bypass, the script interacts directly with Nacos administrative user-management APIs under /nacos/v1/auth/users. Capabilities implemented in code are broader than simple detection: it can check vulnerability by attempting to list users, enumerate existing users, create a new user with attacker-chosen credentials, delete an existing user, and update/reset a user's password. This makes it an operational exploit rather than a detection-only script. Repository structure is minimal and straightforward. README.md provides context, impact, affected versions, and remediation. exploit.py contains a NacosExploit class with helper request logic, individual methods for each administrative action, CLI argument parsing, and a main() routine. The script supports target selection, optional SSL verification disabling, and action flags (--check, --list, --create, --delete, --update-password). It prints status codes and optionally formats output with the rich library if installed. No reverse shell or post-exploitation implant is included; the payload is the crafted HTTP interaction itself. The primary security impact is unauthorized administrative access to Nacos user management over the network.
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26 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An Alibaba Nacos vulnerability listed among vulnerabilities actively exploited or operationally weaponized in July 2026.
An authentication bypass vulnerability in Nacos that was chained with the Langflow flaw during the JadePuffer campaign.
An authentication bypass vulnerability in Nacos that enabled JadePuffer to forge JWTs and create administrative access during lateral movement and privilege escalation.
Старая уязвимость в Nacos, использованная той же группой в отдельной кампании против Java-систем компаний для кражи конфигурационных файлов и секретов.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.