CVE-2025-5866: A vulnerability classified as critical has been found in RT-Thread 5.1.0

This month

HIGH 8.0MITIGATE

CVE-2025-5866 is a high-severity flaw (CVSS 8.0) affecting rt-thread. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.0 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-119, CWE-129
Published	2025-06-09
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: rt-thread

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-06-09 07:15 UTCPublished CVE record published
2026-06-17 09:48 UTCUpdated Record last modified

rt-thread rt-thread MITIGATE

Affected: 5.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.1.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-5866?

rt-thread: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-5866 being exploited?

CVE-2025-5866 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-5866 affect?

CVE-2025-5866 affects rt-thread. Severity is high (CVSS 8.0). 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 arr

How urgent is CVE-2025-5866?

Priority 47/100. High severity; Public exploit reference

Related CVEs

CVE-2025-6693 HIGH 7.8 UPGRADE A vulnerability, which was classified as critical, was found in RT-Thread up to 5.1.0
CVE-2025-5869 HIGH 8.0 MITIGATE A vulnerability, which was classified as critical, was found in RT-Thread 5.1.0
CVE-2025-5868 HIGH 8.0 MITIGATE A vulnerability, which was classified as critical, has been found in RT-Thread 5.1.0
CVE-2025-5867 HIGH 8.0 MITIGATE A vulnerability classified as critical was found in RT-Thread 5.1.0
CVE-2025-5865 HIGH 8.0 DOWNGRADE A vulnerability was found in RT-Thread 5.1.0

References

← Back to latest CVEs