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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.

PUBLISHED Reserved 2026-04-06 | Published 2026-04-21 | Updated 2026-04-21 | Assigner GitHub_M




LOW: 3.1CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

Problem types

CWE-400: Uncontrolled Resource Consumption

CWE-674: Uncontrolled Recursion

CWE-770: Allocation of Resources Without Limits or Throttling

Product status

< 2.5.3
affected

References

github.com/...penbao/security/advisories/GHSA-r65v-xgwc-g56j exploit

github.com/...penbao/security/advisories/GHSA-r65v-xgwc-g56j

cve.org (CVE-2026-39396)

nvd.nist.gov (CVE-2026-39396)

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