Vulnerability 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.
CVSS Score
LOW
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openbao | Openbao | < 2.5.3 |
Related Weaknesses (CWE)
References
- https://github.com/openbao/openbao/security/advisories/GHSA-r65v-xgwc-g56jExploitVendor Advisory
- https://github.com/openbao/openbao/security/advisories/GHSA-r65v-xgwc-g56jExploitVendor Advisory
FAQ
What is CVE-2026-39396?
CVE-2026-39396 is a vulnerability with a CVSS score of 3.1 (LOW). 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 imag...
How severe is CVE-2026-39396?
CVE-2026-39396 has been rated LOW with a CVSS base score of 3.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39396?
Check the references section above for vendor advisories and patch information. Affected products include: Openbao Openbao.