CVE-2025-12970: The extract_name function in Fluent Bit in_docker input plugin copies container names into a fixed size stack buffer without validating length. An attacker who…

PriorityP260high8.8CVSS 3.1

AVNACLPRLUINSUCHIHAH

EPSS

0.79%

51.6th percentile

The extract_name function in Fluent Bit in_docker input plugin copies container names into a fixed size stack buffer without validating length. An attacker who can create containers or control container names, can supply a long name that overflows the buffer, leading to process crash or arbitrary code execution.

Affected

5 ranges

Vendor	Product	Version range	Fixed in
fluentbit	fluent_bit	< 4.0.12	4.0.12
msrc	azl3_fluent-bit_3.1.10-2_on_azure_linux_3.0	—	—
msrc	azl3_fluent-bit_3.1.9-6_on_azure_linux_3.0	—	—
msrc	cbl2_fluent-bit_3.0.6-4_on_cbl_mariner_2.0	—	—
treasuredata	fluent_bit	—	—

Detection & IOCsextracted from sources · hover to see the quote

→The vulnerable function is `extract_name` in Fluent Bit's `in_docker` input plugin. Monitor for Fluent Bit process crashes (unexpected termination/segfault) when the Docker input plugin is active, which may indicate exploitation attempts via oversized container names. ↗
→An attacker exploiting this vulnerability must be able to create containers or control container names. Audit container creation events for unusually long container names, which could be a precursor to or indicator of exploitation. ↗

·This vulnerability is only exploitable when the Fluent Bit `in_docker` input plugin is enabled. Deployments not using the Docker input plugin are not affected. ↗
·CBL-Mariner (Azure Linux) users require a package update. Microsoft has flagged this as requiring customer action for Mariner-based deployments. ↗

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

vendor_msrc8.8HIGH

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.