OpenBao up to 2.5.2 OCI Plugin ExtractPluginFromImage resource consumption

Summaryinfo

A vulnerability marked as problematic has been reported in OpenBao up to 2.5.2. The affected element is the function ExtractPluginFromImage of the component OCI Plugin. The manipulation leads to resource consumption. This vulnerability is uniquely identified as CVE-2026-39396. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in OpenBao up to 2.5.2. It has been rated as problematic. This issue affects the function ExtractPluginFromImage of the component OCI Plugin. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. The summary by CVE is:

OpenBao is an open source identity-based secrets management system. Prior to version 2.5.3, `ExtractPluginFromImage()` in OpenBao's OCI plugin downloader extracts a plugin binary from a container image by streaming decompressed tar data via `io.Copy` with no upper bound on the number of bytes written. An attacker who controls or compromises the OCI registry referenced in the victim's configuration can serve a crafted image containing a decompression bomb that decompresses to an arbitrarily large file. The SHA256 integrity check occurs after the full file is written to disk, meaning the hash mismatch is detected only after the damage (disk exhaustion) has already occurred. This allow the attacker to replace **legit plugin image** with no need to change its signature. Version 2.5.3 contains a patch.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-39396 since 04/07/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 311376 (Fedora 44 : openbao (2026-c7450bfed6)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.5.3 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (311376) and CERT Bund (WID-SEC-2026-1189). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Open Source OpenBao

Productinfo

Name

• OpenBao

Version

• 2.5.0
• 2.5.1
• 2.5.2

Website

• Product: https://github.com/openbao/openbao/

CPE 2.3info

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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