CVE-2025-5866
Published: 09 June 2025
Summary
CVE-2025-5866 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Rt-Thread Rt-Thread. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 20.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis
A critical vulnerability has been identified in RT-Thread version 5.1.0 within the sys_sigprocmask function of rt-thread/components/lwp/lwp_syscall.c. The issue stems from improper validation of an array index when the "how" argument is manipulated, corresponding to CWE-129 and CWE-119 weaknesses that can result in out-of-bounds memory access.
An attacker with low privileges on an adjacent network can supply a crafted argument to trigger the flaw, achieving high impact on confidentiality, integrity, and availability of the affected system according to the CVSS 4.0 vector AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H.
The EPSS score remains flat at 0.0117 with no material increase since disclosure, and no public indicators of active exploitation have been reported.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-17438
Vulnerability details
A vulnerability classified as critical has been found in RT-Thread 5.1.0. This affects the function sys_sigprocmask of the file rt-thread/components/lwp/lwp_syscall.c. The manipulation of the argument how leads to improper validation of array index.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The improper array index validation in sys_sigprocmask allows out-of-bounds access from user space, enabling kernel crashes (Endpoint DoS via system exploitation, T1499.004) and potential privilege escalation through unauthorized kernel memory access (T1068).
MITRE ATLAS TechniquesAI
MITRE ATLAS techniques
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.
Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.
Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.
Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.