CVE-2025-66409VulnerabilityPublished 2 Dec 2025

CVE-2025-66409: espressif esp-idf · Out-of-bounds Read

Affects espressif esp-idfSource CVE Database V5

Not known to be exploited · CVSS 2.7 Low.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

2.7Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: Unreported

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: Unreported: Based on threat intelligence sources each of the following must apply: · No knowledge of publicly available proof-of-concept · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubespressif/esp-idf`pkg:github/espressif/esp-idf`Other threats	Affected <=5.1.6	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2025-66409, European organizations should: 1) Monitor Espressif's official channels for patches addressing this vulnerability and plan timely updates to ESP-IDF versions beyond 5.5.1 once available. 2) If immediate patching is not feasible, disable AVRCP functionality on ESP32 devices where it is not required to eliminate the attack vector. 3) Implement Bluetooth device access controls and network segmentation to limit exposure of vulnerable devices to untrusted Bluetooth peers. 4) Employ Bluetooth monitoring tools to detect anomalous or malformed VENDOR DEPENDENT commands indicative of exploitation attempts. 5) For critical deployments, conduct security assessments of ESP32 device firmware and Bluetooth stack configurations to ensure no additional vulnerabilities are present. 6) Educate operational teams on the risks associated with Bluetooth-enabled IoT devices and enforce policies restricting unauthorized Bluetooth connections. These targeted measures go beyond generic advice by focusing on the specific vulnerability vector and device configurations.

Description

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In 5.5.1, 5.4.3, 5.3.4, 5.2.6, 5.1.6, and earlier, when AVRCP is enabled on ESP32, receiving a malformed VENDOR DEPENDENT command from a peer device can cause the Bluetooth stack to access memory before validating the command buffer length. This may lead to an out-of-bounds read, potentially exposing unintended memory content or causing unexpected behavior.

Impact

For European organizations, the impact of CVE-2025-66409 is generally low but context-dependent. Organizations deploying ESP32-based IoT devices with Bluetooth AVRCP enabled—such as smart home devices, industrial sensors, or consumer electronics—may face risks of unintended memory disclosure or device instability if targeted by attackers within Bluetooth range. Although the vulnerability does not allow remote code execution or privilege escalation, information leakage could aid attackers in further reconnaissance or targeted attacks. Critical infrastructure sectors using ESP32 devices in operational technology environments might be more sensitive to device reliability issues caused by unexpected behavior. However, the limited attack surface (Bluetooth proximity required) and low severity reduce the overall risk. Still, organizations with large-scale IoT deployments should consider the cumulative risk and potential for chained exploits. The absence of known exploits in the wild suggests limited current threat activity, but proactive mitigation is advisable to prevent future exploitation.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 2 Dec 2025, 19:21 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

Related threats