CVE-2026-39396
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.
Does this matter?
Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- EPSS
- 0.22% probability · 12th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-674, CWE-770
- Affected
- openbao/openbao
- Source
- security-advisories@github.com
References
- https://github.com/openbao/openbao/security/advisories/GHSA-r65v-xgwc-g56jExploit, Vendor Advisory
- https://github.com/openbao/openbao/security/advisories/GHSA-r65v-xgwc-g56jExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.