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.

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History

Tue, 21 Apr 2026 02:45:00 +0000

Type Values Removed Values Added
First Time appeared Openbao
Openbao openbao
Vendors & Products Openbao
Openbao openbao

Tue, 21 Apr 2026 01:15:00 +0000

Type Values Removed Values Added
Description 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.
Title OpenBao has Decompression Bomb via Unbounded Copy in OCI Plugin Extraction (DoS)
Weaknesses CWE-400
CWE-674
CWE-770
References
Metrics cvssV3_1

{'score': 3.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-21T00:44:53.943Z

Reserved: 2026-04-06T22:06:40.516Z

Link: CVE-2026-39396

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-21T01:16:06.507

Modified: 2026-04-21T01:16:06.507

Link: CVE-2026-39396

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-21T02:30:25Z

Weaknesses