Cybersecurity researchers have discovered five vulnerabilities in Fluent Bit, an open-source telemetry agent, that could be combined to compromise and take over cloud infrastructures.
See also: Vulnerability in vLLM allows RCE attacks
The security flaws “ allow attackers to bypass authentication, perform file traversal, achieve remote code execution, cause denial of service conditions, and manipulate labels, ” Oligo Security said in a report.
Successful exploitation of the vulnerabilities could allow attackers to disrupt cloud services, manipulate data, and penetrate deeper into cloud and Kubernetes infrastructure. The list of vulnerabilities identified is as follows:
– **CVE-2025-12972** – A file path vulnerability resulting from the use of unsanitized label values to generate output file names, making it possible to write or overwrite arbitrary files to disk, allowing log file corruption and remote code execution.
– **CVE-2025-12970** – A buffer overflow vulnerability in the Docker Metrics input plugin (in_docker) that could allow attackers to cause code execution or crash the agent by creating containers with excessively long names.
– **CVE-2025-12978** – A vulnerability in tag mapping logic allows attackers to intercept trusted tags – assigned to each event imported by Fluent Bit – by guessing just the first character of a Tag_Key, allowing an attacker to redirect logs, bypass filters, and inject malicious or misleading files under trusted tags.
– **CVE-2025-12977** – An improper validation of input labels coming from user-controlled fields, allowing an attacker to insert newlines, path sequences, and control characters that can corrupt downstream logs.
– **CVE-2025-12969** – Lack of security.users in the in_forward plugin used to receive logs from other Fluent Bit instances using the Forward protocol, allowing attackers to send logs, inject fake telemetry, and flood a security product's logs with false events.
See also: RCE vulnerability hits AI export frameworks at Meta, Nvidia and Microsoft
The CERT Coordination Center (CERT/CC), in an independent advisory, said that many of these vulnerabilities require an attacker to have network access to a Fluent Bit instance, adding that they could be used for authentication bypass, remote code execution, denial of service, and tag manipulation.
Following responsible disclosure, the issues have been addressed in versions 4.1.1 and 4.0.12 released last month. Amazon Web Services (AWS), which also participated in the coordinated disclosure, has urged customers using Fluent Bit to update to the latest version for optimal protection.
Given the popularity of Fluent Bit in enterprise environments, the flaws have the potential to impact access to cloud services, allow data corruption, and take over the logging service itself.
Other recommended actions include avoiding the use of dynamic labels for routing, locking output and destination paths to prevent label-based expansion or routing, mounting /fluent-bit/etc/ and configuration files as read-only to block corruption at runtime, and running the service as non-root users.
See also: Critical RCE Vulnerability in Anthropic's Claude Desktop
🔒 Protect your privacy with Proton VPN
Swiss VPN from the creators of Proton Mail — strict no-logs policy, strong encryption, and built-in NetShield that blocks ads, trackers, & malware.
- ✔ No-logs, based in Switzerland (except 14-Eyes)
- ✔ NetShield: blocks ads, trackers & malicious domains
- ✔ Covers all devices — free version available
The link is an affiliate link — SecNews may receive a commission at no additional cost to you. It does not affect the independence of our article writing.
The development comes more than a year after Tenable reported a vulnerability in Fluent Bit's built-in HTTP server (CVE-2024-4323, also known as Linguistic Lumberjack) that could be exploited to achieve denial of service (DoS), information disclosure, or remote code execution.
