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Rt Thread EUVDEUVD-2025-17440

| CVE-2025-5865 HIGH
Buffer Overflow (CWE-119)
2025-06-09 cna@vuldb.com
8.0
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

The CVSS 3.1 vector (AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) indicates moderate attack complexity with adjacency-level network access requirements and low privilege escalation needed. The score of 8.0 reflects high impact across confidentiality, integrity, and availability. However, the attack vector (AV:A - adjacent network) and privilege requirement (PR:L - low privilege) significantly constrain real-world exploitability compared to network-accessible vulnerabilities. The memory corruption nature suggests high technical impact if exploited successfully. Without disclosed EPSS scores, KEV status confirmation, or public POC availability, the practical exploitation probability appears moderate—this requires legitimate local/adjacent access and existing user privileges. The vulnerability is serious for networked IoT/embedded deployments where multiple processes or adjacent devices may be untrusted, but is less critical for single-user or isolated systems. Organizations running RT-Thread 5.1.0 in multi-tenant or exposed network environments should treat this as high priority.

Exploit ScenarioDerived

An authenticated attacker with local user-level access to an RT-Thread 5.1.0 system (or adjacent network access in multi-process IoT scenarios) crafts a malicious application that calls select() with a specially crafted timeout parameter pointing to an invalid or out-of-bounds memory address. The lwp syscall handler fails to validate this pointer before dereferencing it in kernel mode, causing either: (1) out-of-bounds memory read/write corrupting kernel data structures, (2) kernel panic/DoS via access violation, or (3) potential code execution if the attacker can overwrite function pointers or kernel code. For example, an IoT device running RT-Thread with multiple user applications might have one compromised app exploiting this to corrupt the kernel's task control block, affecting all running processes. No public POC is known, but the straightforward nature of the bug (missing bounds check on a syscall parameter) means exploitation would be relatively straightforward once details are widely known.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 14, 2026

Critical memory corruption vulnerability in RT-Thread 5.1.0's sys_select syscall handler that allows authenticated local attackers to corrupt kernel memory by manipulating the timeout parameter. The vulnerability affects the lwp (lightweight process) component and has a CVSS score of 8.0 with potential for code execution, information disclosure, and denial of service. No public exploit code or active in-the-wild exploitation has been confirmed at this time, but the critical severity rating and memory corruption nature warrant immediate patching.

RemediationAI

Immediate patching is required. RT-Thread developers should have released a patched version following CVE disclosure. Users should: 1) Update to the latest RT-Thread version >= 5.1.1 or apply the security patch from the vendor; 2) The fix involves proper validation and bounds-checking of the timeout parameter in sys_select before kernel use, including verification that the timeout pointer is accessible in user-space and safe for kernel-mode dereferencing; 3) If immediate patching is not feasible, disable or restrict use of select() syscalls where possible, or limit process privilege levels to reduce attack surface. Vendor advisory links and patch binaries should be obtained from the official RT-Thread GitHub repository (https://github.com/RT-Thread/rt-thread) or security advisories page. Enable kernel memory protection features (ASLR, DEP/NX if supported) to limit exploitation impact.

Affected VersionsENISA

RT-Thread 5.1.0

Affected Packages

euvd rt_thread no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

RT-Thread is a real-time operating system commonly deployed in embedded and IoT devices. The vulnerability exists in rt-thread/components/lwp/lwp_syscall.c, specifically in the sys_select function which implements the POSIX select() syscall. The lwp component provides lightweight process support and user-space syscall handling. CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) indicates an out-of-bounds memory access issue. The root cause is insufficient validation of the timeout parameter before it is accessed in kernel mode and stored in kernel memory. The timeout parameter, when passed from user-space applications, is not properly checked for validity before kernel use, allowing attackers to write arbitrary values to kernel memory regions or cause buffer overflows. This is a classic boundary condition vulnerability in kernel parameter marshalling where user-supplied data crosses the privilege boundary without adequate sanitization.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.0 HIGH
AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
PoC Detected
Jul 11, 2025 - 18:22 vuln.today
Public exploit code
CVE Published
Jun 09, 2025 - 07:15 nvd
HIGH 8.0

DescriptionCVE.org

A vulnerability was found in RT-Thread 5.1.0. It has been rated as critical. Affected by this issue is the function sys_select of the file rt-thread/components/lwp/lwp_syscall.c of the component Parameter Handler. The manipulation of the argument timeout leads to memory corruption. The vendor explains, that "[t]he timeout parameter should be checked to check if it can be accessed correctly in kernel mode and used temporarily in kernel memory."

Executive ViewAI

Why It Matters

RT-Thread 5.1.0 contains a critical memory corruption vulnerability in its parameter handling that could allow attackers to crash systems or execute arbitrary code with a public exploit already available. Organizations running RT-Thread in embedded or IoT environments face immediate risk of service disruption and potential data compromise until a patch is released.

Business Impact: High
Compensating Controls

Implement network-level access controls to restrict connections to affected RT-Thread services; disable or limit use of sys_select functionality if application logic permits; deploy runtime monitoring to detect suspicious parameter passing patterns; consider isolating affected systems to air-gapped or restricted networks until patching is available; monitor vendor advisories for patch release timeline.

Threat Intelligence Overview

EPSS Score
0.5%
Top 35% exploitable
Exploit
POC
Public exploit code exists
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.5%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
High

Priority Score

60
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +40
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

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