CVE-2026-41857: BOSH CLI Command Injection on Operator Workstations

Technical summary

CVE-2026-41857 is a command injection vulnerability in the BOSH CLI where an attacker controlling or compromising a BOSH Director can achieve arbitrary code execution on an operator's local machine. The vulnerability exists in the bosh ssh, bosh scp, and bosh logs -f commands when run with their default configuration flags. The attack vector is local (the operator's workstation), the attack complexity is low, no privileges are required on the target machine, and user interaction (running the command) is necessary. The flaw is classified as CWE-78 (OS Command Injection) and carries a CVSS 3.0 score of 7.8 (HIGH severity).

Business impact

Operators who interact with BOSH-managed infrastructure face direct compromise of their workstations when connecting to a malicious or breached BOSH Director. This can lead to theft of credentials, SSH keys, cloud API tokens, or other sensitive material stored on the operator's machine. In environments where operators have broad access to multiple systems or cloud accounts, a single compromised workstation can cascade into infrastructure-wide compromise. Teams relying on BOSH should assume that any unpatched CLI instances are vulnerable if they interact with untrusted or potentially compromised Directors.

Affected systems

Cloud Foundry BOSH CLI versions prior to 7.10.5 are vulnerable. Any operator using an affected version and running bosh ssh, bosh scp, or bosh logs -f commands against a BOSH Director is at risk. The vulnerability does not affect the BOSH Director itself, only the CLI tool used to interact with it.

Exploitability

Exploitation requires control or compromise of a BOSH Director and the target operator to run a vulnerable CLI command against that Director. The operator must consciously initiate the command, but no special user interaction beyond that is required—the exploit triggers automatically within the default command behavior. The low attack complexity and high impact make this a practical concern for teams using shared or internet-facing BOSH Directors, or for supply-chain scenarios where an operator's trust in a Director is misplaced. Public exploit code is not required; a malicious Director response is sufficient.

Remediation

Upgrade BOSH CLI to version 7.10.5 or later. This is a straightforward patch that closes the injection vector. Operators should verify their installed CLI version using bosh --version and update via their package manager or download the latest release. No configuration changes or mitigation without patching are documented as fully effective.

Patch guidance

Update BOSH CLI to version 7.10.5 or later. The patch is available through standard distribution channels. Verify the update by running bosh --version and confirming output shows 7.10.5 or higher. No breaking changes are anticipated; this is a security patch. For environments managing multiple operators, consider centralizing or automating CLI distribution to ensure uniform patching.

Detection guidance

Monitor for unexpected child processes spawned by bosh CLI commands, particularly shell invocations or network connections initiated from bosh ssh, bosh scp, or bosh logs sessions. Check operator workstation logs (process creation events, command execution history) for anomalous activity during or immediately after BOSH CLI use. Audit BOSH Director logs for unusual or malformed responses to CLI commands. Additionally, verify that all operators have upgraded to CLI version 7.10.5+ by scanning deployed CLI binaries or querying version output from operator machines.

Why prioritize this

This vulnerability merits immediate patching because it provides direct code execution on operator workstations with a low barrier to exploitation (no special privileges needed, default flags vulnerable). The impact is high—credential and key theft—and the blast radius extends to any system the operator can access. Although the KEV catalog does not currently list this vulnerability and public exploit code is not confirmed to exist, the technical severity (CVSS 7.8 HIGH) and the practical ease of weaponizing a compromised Director make this a top priority for any team running BOSH. Delay creates accumulating risk if Directors are exposed or compromised.

Risk score, explained

The CVSS 3.0 score of 7.8 (HIGH) reflects a local attack vector combined with high confidentiality, integrity, and availability impact. The score is driven by the operator's broad access to the compromised machine and the ability to steal credentials or alter system state. Attack complexity is low (default flags are vulnerable), and no privileges are pre-required on the target workstation, making the barrier to successful exploitation low. The score does not reach CRITICAL because user interaction (running the CLI command) is required; this is not an unauthenticated network attack or silent local privilege escalation.

Frequently asked questions