CVE-2026-58004

Executive Summary

CVE-2026-58004 is an out-of-bounds read vulnerability (CWE-125) in Altera Trusted Firmware running on the Hard Processor System (HPS) of Altera SoC FPGA platforms, present through release socfpga_v2.14.0. It allows a privileged local actor to trigger out-of-bounds memory reads that result in privilege escalation and memory/buffer overflow conditions. With a CVSS 3.1 base score of 8.1 (High), the flaw is significant on affected devices, but exploitation requires local access and elevated privileges prior to the attack, and no public proof-of-concept, exploit code, Nuclei template, or CISA KEV listing currently exists.

Technical Analysis

The NVD description states the issue is an out-of-bounds read (CWE-125) affecting Altera Trusted Firmware on HPS, and that it "allows Privilege Escalation and Overflow Buffers." The affected code line is bounded by the version range "through socfpga_v2.14.0."

Trusted Firmware is a security-focused runtime that executes in a privileged exception level (Arm Trusted Firmware / TF-A class of component, running in EL3 on Arm-based HPS subsystems). Because it operates at the highest privilege level, any memory-safety defect inside it is consequential: code that reads beyond the bounds of an intended buffer cannot obtain trusted data and — per the description — is associated with a subsequent buffer overflow condition ("Overflow Buffers"). The combination of an out-of-bounds read and an overflow in a privileged firmware component provides the technical basis for the privilege-escalation impact described.

The exact function, module, buffer, and attacker-controlled parameter are not disclosed in the available NVD description or CNA title. No code-level detail (function names, service identifiers, IPC/SMC call numbers, or file paths) can be derived from the supplied data, and none is fabricated here. The vulnerability class (out-of-bounds read), the executing component (Altera Trusted Firmware on HPS), and the version ceiling (socfpga_v2.14.0) are the only confirmed technical facts.

Attack-surface reasoning that is derivable from the data: the flaw is reachable on the HPS of Altera SoC FPGA devices via a local vector (AV:L) and requires high privileges (PR:H), with scope change (S:C) — i.e., the impact crosses a security boundary into a more privileged context. This is consistent with a flaw that is triggered by a caller already operating with some elevated access and that, when exploited, compromises the trusted execution boundary.

Exploitation Scenarios

No public proof-of-concept is available; the attack chain below is inferred strictly from the vulnerability class and CVSS metrics. No specific function names or parameters are asserted.

1. Reconnaissance / target identification. An attacker achieves access to an Altera SoC FPGA platform running Trusted Firmware on HPS at or below socfpga_v2.14.0. Given the required privilege level (PR:H), the operator already possesses a privileged foothold on the platform (for example, a high-privilege process or an already-compromised privileged context on the HPS), rather than relying on remote reachability. Target identification is local and deterministic: enumerate the firmware release to confirm the socfpga_v2.14.0-or-earlier exposure.

2. Triggering the flaw. Acting from that privileged, local position, the attacker invokes the firmware entry point that processes the affected, insufficiently validated data. Because the defect is an out-of-bounds read (CWE-125), the trigger is a crafted request/input that causes the firmware to read past the intended boundary of a buffer. The description pairs this with a buffer-overflow outcome, meaning the crafted input drives the trusted code path beyond its safe bounds. The precise call interface cannot be specified from the supplied data.

3. Payload / execution method (class level). Exploitation manipulates the out-of-bounds read to influence control flow or data handling inside the Trusted Firmware component, in conjunction with the described buffer overflow. At the vulnerability-class level, this is a memory-corruption exploitation path against a component executing at the highest privilege level.

4. Post-exploitation impact. Successful exploitation yields privilege escalation (per the CVE description and the scope-changed CVSS metric) and memory corruption in Trusted Firmware. With Integrity and Availability rated High, the attacker can corrupt trusted firmware state and disrupt the trusted execution environment on the device; Confidentiality is rated Low, consistent with the out-of-bounds read being limited in the data it exposes but still impactful for control/integrity.

Impact Assessment

Affected systems are Altera SoC FPGA platforms whose HPS runs Trusted Firmware at or below socfpga_v2.14.0. These components sit beneath the operating system and enforce security boundaries on the device, so compromise carries device-wide consequences within the affected security scope.

CVSS 3.1 subscores (base 8.1, High):

• Attack Vector: Local (L) — the attacker must already have local execution capability on the target.
• Attack Complexity: Low (L) — no special conditions beyond the crafted local input are implied.
• Privileges Required: High (H) — a privileged position is needed before exploitation.
• User Interaction: None (N) — no victim action is required.
• Scope: Changed (C) — impact crosses into a more privileged security context, the strongest indicator of the escalation value.
• Confidentiality: Low (L), Integrity: High (H), Availability: High (H) — limited data exposure, but substantial integrity and availability damage in the trusted component.

Blast radius: the local privilege requirement and high-privilege precondition constrain mass exploitation, but where an operator already holds a privileged foothold, the scope change means the flaw can defeat the trusted boundary the platform relies on. No exploitation in the wild, no KEV listing, and no public exploit are currently reported. EPSS has not yet been scored by FIRST.org.

Detection Guidance

Sigma Rule

title: Potential Altera Trusted Firmware HPS Out-of-Bounds Read Exploitation (CVE-2026-58004)
id: 8f2c1d64-3b7a-4c1e-9d55-altera58004
status: experimental
description: Detects anomalous privileged access to Trusted Firmware / HPS interfaces consistent with attempts to exploit CVE-2026-58004
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-58004
author: valtersit.com
date: 2026-01-01
logsource:
  product: linux
  category: process_creation
detection:
  selection:
    Image|endswith:
      - '/dev/mem'
      - '/dev/kmem'
    CommandLine|contains:
      - 'socfpga'
      - 'trusted-firmware'
      - 'atf'
  condition: selection
falsepositives:
  - Legitimate firmware update tooling
  - Authorized low-level diagnostics
level: high
tags:
  - attack.privilege_escalation
  - attack.t1068
  - cve.2026.58004

YARA Rule

rule CVE_2026_58004_Altera_TrustedFirmware_Exploit_Marker
{
    meta:
        description = "Detects artifacts referencing Altera Trusted Firmware HPS exploitation for CVE-2026-58004"
        author = "valtersit.com"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-58004"
        cve = "CVE-2026-58004"

    strings:
        $a = "socfpga_v2.14.0" ascii wide
        $b = "trusted-firmware" ascii wide
        $c = "CVE-2026-58004" ascii wide
        $d = "HPS" ascii wide

    condition:
        (uint16(0) == 0x5A4D or uint32(0) == 0x464C457F) and
        any of ($a, $b) and $c
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-58004 Altera Trusted Firmware HPS Out-of-Bounds Read Exploitation Attempt"; flow:established,to_server; content:"socfpga"; http_uri; nocase; content:"trusted-firmware"; http_header; nocase; reference:cve,2026-58004; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-58004; classtype:attempted-admin; sid:202658004; rev:1;)

Elastic Detection

process where process.name in ("devmem", "busybox", "flash_erase")
  and process.args : ("*socfpga*" or "*trusted-firmware*" or "*0xF*")

Note: rule matches anomalous privileged device access consistent with the firmware exploitation path; tune arguments to local tooling inventory.

Splunk SPL Query

index=main sourcetype=linux_secure OR sourcetype=syslog
| search ("socfpga" OR "trusted-firmware" OR "HPS")
| stats count min(_time) as first_seen max(_time) as last_seen by host, user, process, message
| where count > 0
| sort - count

Wazuh OSSEC Rule

<group name="altera,cve-2026-58004,">
  <rule id="10058004" level="12">
    <decoded_as>syslog</decoded_as>
    <match>socfpga|trusted-firmware|HPS</match>
    <description>CVE-2026-58004: Possible Altera Trusted Firmware HPS out-of-bounds read / privilege escalation attempt</description>
    <mitre>
      <id>T1068</id>
    </mitre>
    <group>privilege_escalation,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix, workaround, affected-version mapping, or OSV package data was identified.

1. Immediate mitigations

   • Restrict and monitor privileged local access to the HPS and any interface that reaches Trusted Firmware; the flaw requires a local, high-privilege actor (AV:L, PR:H), so reducing who holds that privilege directly reduces exposure.
   • Apply the principle of least privilege to processes and accounts capable of interacting with firmware or low-level device interfaces; remove unnecessary privileged access.
   • Treat all devices confirmed running socfpga_v2.14.0 or earlier as exposed until a fixed release is identified; isolate or denylist such platforms from untrusted local workflows where feasible.
   • Maintain integrity monitoring of the trusted firmware component to detect unauthorized modification.

2. Patch / upgrade steps

   • There is currently no patch evidence from any tracked source. Monitor the Altera / vendor security advisory channels and the NVD entry for a fixed Trusted Firmware release above socfpga_v2.14.0.
   • Do not assume any specific version resolves the issue until the vendor publishes an advisory. Once a fixed release is available, validate it against the NVD reference and stage upgrades through change control on affected SoC FPGA platforms.

3. Long-term hardening

   • Track Altera Trusted Firmware security advisories and CVEs as part of firmware supply-chain monitoring for FPGA/SoC platforms.
   • Adopt memory-safety-hardened build configurations and boundary-checking practices for trusted firmware where vendor support allows.
   • Integrate local firmware access and device-interface events into SOC telemetry so that attempts to reach privileged HPS components are logged and alerted (see Detection Guidance).
   • Re-evaluate the CVSS scope-changed nature of this flaw: since device compromise crosses a security boundary, include it in trusted-execution-environment threat models for the platform.

References

• NVD — CVE-2026-58004: https://nvd.nist.gov/vuln/detail/CVE-2026-58004
• CWE-125 — Out-of-bounds Read: https://cwe.mitre.org/data/definitions/125.html
• MITRE ATT&CK T1068 — Exploitation for Privilege Escalation: https://attack.mitre.org/techniques/T1068/
• CVSS v3.1 Specification: https://www.first.org/cvss/v3.1/specification-document
• Altera / Intel SoC FPGA Trusted Firmware documentation and security advisory channels (vendor advisory pending; no CVE-specific advisory was available at the time of writing)

Threat actor campaigns / exploit-in-the-wild: none reported. CISA KEV: not listed. Public PoC / exploit code / Nuclei template: none identified. EPSS: not yet scored by FIRST.org.