Bug 2459958 (CVE-2026-39396)

Summary: CVE-2026-39396 OpenBao: OpenBao: Denial of Service via decompression bomb in OCI plugin extraction
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in OpenBao. An attacker who controls or compromises the Open Container Initiative (OCI) registry can exploit a vulnerability in OpenBao's OCI plugin downloader. By serving a specially crafted container image, the attacker can cause the system to decompress an arbitrarily large file, leading to disk exhaustion. This can result in a Denial of Service (DoS), making the system unavailable.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2460058, 2460059    
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Description OSIDB Bzimport 2026-04-21 02:02:18 UTC 
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.