CVE-2025-52471
ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. An integer underflow vulnerability has been identified in the ESP-NOW protocol implementation within the ESP Wi-Fi component of versions 5.4.1, 5.3.3, 5.2.5, and 5.1.6 of the ESP-IDF framework. This issue stems from insufficient validation of user-supplied data length in the packet receive function. Under certain conditions, this may lead to out-of-bounds memory access and may allow arbitrary memory write operations. On systems without a memory protection scheme, this behavior could potentially be used to achieve remote code execution (RCE) on the target device. In versions 5.4.2, 5.3.4, 5.2.6, and 5.1.6, ESP-NOW has added more comprehensive validation logic on user-supplied data length during packet reception to prevent integer underflow caused by negative value calculations. For ESP-IDF v5.3 and earlier, a workaround can be applied by validating that the data_len parameter received in the RX callback (registered via esp_now_register_recv_cb()) is a positive value before further processing. For ESP-IDF v5.4 and later, no application-level workaround is available. Users are advised to upgrade to a patched version of ESP-IDF to take advantage of the built-in mitigation.
| Software | From | Fixed in |
|---|---|---|
| espressif / esp-idf | 5.1.6 | 5.1.6.x |
| espressif / esp-idf | 5.2.5 | 5.2.5.x |
| espressif / esp-idf | 5.3.3 | 5.3.3.x |
| espressif / esp-idf | 5.4.1 | 5.4.1.x |
- https://github.com/espressif/esp-idf/commit/b1a379d57430d265a53aca13d59ddfbf2e7ac409
- https://github.com/espressif/esp-idf/commit/c5fc81917805f99e687c81cc56b68dc5df7ef8b5
- https://github.com/espressif/esp-idf/commit/d4dafbdc3572387cd4f9a62b776580bc4ac3bde7
- https://github.com/espressif/esp-idf/commit/d6ec5a52255b17c1d6ef379e89f9de2c379042f8
- https://github.com/espressif/esp-idf/commit/df7757d8279871fa7a2f42ef3962c6c1ec88b8a2
- https://github.com/espressif/esp-idf/commit/edc227c5eaeced999b5212943a9434379f8aad80
- https://github.com/espressif/esp-idf/security/advisories/GHSA-hqhh-cp47-fv5g
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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
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