BOSH CLI EUVD-2026-42507

Exploitation requires the victim to run the BOSH CLI against a release whose config/blobs.yml contains a maliciously crafted path key with directory-traversal sequences - i.e., an operator or CI/CD job must sync, download, or otherwise process an attacker-supplied or tampered release (UI:A). No authentication to the CLI is required (PR:N) and attack complexity is low (AC:L), but the traversal only fires during a blob sync/download operation. Limiting factors: the attacker must first get their malicious blobs.yml in front of the victim (supply-chain foothold or a compromised/untrusted release), and impact is bounded by the filesystem privileges of the account running the CLI, so trusted-release-only workflows and least-privilege execution substantially reduce real-world exposure.

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N) describes a network-delivered, low-complexity, unauthenticated issue with high confidentiality and integrity impact but no availability impact, gated by user/operator interaction (UI:A) - the victim must run the CLI against a malicious blobs.yml. This is a real-but-conditional risk: it is not a remotely-triggerable server flaw, so it will not be mass-exploited like a network daemon RCE, but it is dangerous in supply-chain and CI/CD contexts where operators sync third-party or tampered releases. EPSS was not provided, and there is no KEV listing and no known POC, which - combined with the UI requirement - points to targeted/supply-chain abuse rather than widespread automated exploitation. Note a tension to verify: VI:H/VC:H (file write plus exfiltration) is a strong impact rating, yet real-world impact depends heavily on the privileges of the account running the CLI and whether operators consume untrusted releases; treat the 8.5 as an upper bound for typical trusted-release workflows.

An attacker publishes or tampers with a BOSH release so its config/blobs.yml contains a path key with traversal sequences pointing outside the blobstore directory. When an operator or CI pipeline runs the BOSH CLI to sync/download that release's blobs, the CLI writes attacker-controlled files to arbitrary host locations and can expose sensitive files, potentially leading to code execution or credential theft depending on the write target. No public POC is known, and success requires the victim to process the malicious release (UI:A).