CVE-2026-65197 in HDM Family-A
Summary
by MITRE • 10/13/2026
H3C HDM Family-A verifies the RSA signature of a firmware image against a public key it reads from the mutable file `/conf/public.pem`. That file is writable by an authenticated Redfish client through the `UpdateService.UploadSignKey` action, which stores the uploaded body verbatim after validating only that the multipart filename ends in `.pem`. An administrator, or any account with `firmware-update` privilege, can therefore replace the trust anchor with their own key, sign a malicious image with the matching private key, and have it pass verification. Family-A has no hardware root-of-trust (no PFR) to catch the substituted key.
This was observed on H3C HDM Family-A G5 HDM 6.14.01. H3C HDM Family-A G3/G5 builds carrying the Redfish/DRE update tree appear to be affected. HDM2 uses a different update path and is not covered by this finding.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability in question represents a critical failure in the firmware integrity verification process within the H3C HDM Family-A management system, specifically affecting versions such as G5 HDM 6.14.01 and related builds with Redfish or DRE update capabilities. The core technical flaw lies in the mechanism used to validate RSA signatures of incoming firmware images. Instead of relying on a static, immutable public key stored in read-only memory or hardware-backed secure storage, the system dynamically reads its trust anchor from a mutable file located at `/conf/public.pem`. This design choice introduces a severe supply chain risk because it allows the verification process itself to be subverted if an attacker gains control over this specific configuration file. The absence of a Hardware Root of Trust, such as Platform Firmware Resilience (PFR), further exacerbates the issue by removing any hardware-level safeguards that might detect or prevent unauthorized modifications to critical security parameters during the boot or update sequence.
The exploitation vector for this vulnerability is facilitated through the Redfish interface via the `UpdateService.UploadSignKey` action. This API endpoint is designed to allow administrators to upload new signing keys, presumably for legitimate key rotation purposes. However, the implementation contains a significant validation deficiency: it only checks that the multipart filename ends with the `.pem` extension before storing the uploaded body verbatim into `/conf/public.pem`. There are no cryptographic validations performed on the content of the file itself, nor is there any restriction preventing an authenticated user from overwriting the existing trust anchor. Consequently, any account possessing firmware-update privileges or administrative access can upload a malicious public key that corresponds to a private key held by the attacker. Once this substitution occurs, all subsequent firmware image uploads will be verified against this new, attacker-controlled public key rather than the original manufacturer-signed key.
The operational impact of this vulnerability is severe and effectively nullifies the integrity guarantees provided by digital signatures in the firmware update process. An authenticated adversary can craft a malicious firmware image signed with their own private key pair. When this image is uploaded to the HDM system, the verification logic will successfully validate the signature against the attacker's public key now stored in `/conf/public.pem`. This allows the installation of compromised firmware that could contain backdoors, data exfiltration mechanisms, or complete control over the managed infrastructure. Since the vulnerability affects the core update mechanism, it enables persistent compromise at a level deeper than typical application-layer attacks, potentially leading to full system takeover and lateral movement within the network environment protected by the HDM appliance.
From a classification perspective, this flaw aligns with CWE-284 Improper Access Control, as authenticated users are permitted actions that undermine security controls without sufficient validation of intent or content integrity. It also relates closely to CWE-327 Use of a Broken or Risky Cryptographic Algorithm when considering the broader context of key management failures, but more accurately fits CWE-695 Use of Low-Level Primitives in an Insecure Manner due to the direct manipulation of cryptographic trust anchors via high-level APIs without proper sanitization. In terms of MITRE ATT&CK mapping, this vulnerability facilitates techniques associated with T1078 Valid Accounts and potentially T1195 Supply Chain Compromise if exploited during firmware updates. The attack path involves gaining valid credentials (T1078) to access the Redfish interface, followed by executing a supply chain compromise strategy where the attacker injects malicious code into the update pipeline by replacing the verification key.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. Administrators should immediately restrict network access to the Redfish management interface, ensuring it is only accessible from trusted administrative subnets or through secure VPN tunnels with strong multi-factor authentication. If possible, firmware updates should be performed using out-of-band methods that do not rely on the vulnerable API endpoint until a patch is available. H3C must release an updated version of the HDM Family-A software that implements strict validation for uploaded public keys, such as verifying key length, format compliance beyond just file extension, and potentially requiring dual-approval or offline verification steps for critical trust anchor changes. Furthermore, future iterations should migrate to a hardware-backed root-of-trust model where signing keys are stored in secure elements like TPMs or dedicated crypto chips that prevent software-based overwriting of the primary verification key. Until patches are applied, monitoring logs for unusual patterns in firmware update requests and restricting write permissions on `/conf/public.pem` at the operating system level can provide a temporary layer of defense against exploitation attempts by local users who might have compromised administrative accounts.