CVE-2025-5865: A vulnerability was found in RT-Thread 5.1.0

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HIGH 8.0DOWNGRADE

CVE-2025-5865 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 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."

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	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-119
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 DOWNGRADE

Affected: 5.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.1.0

1. Check installed version

apt-cache policy rt-thread || rpm -q rt-thread || rt-thread --version

2. No fixed release: DOWNGRADE to a release before 5.1.0 (Debian / Ubuntu)

apt-cache madison rt-thread sudo apt install rt-thread=<VERSION_BEFORE_5.1.0> sudo apt-mark hold rt-thread

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list rt-thread sudo dnf downgrade rt-thread-<VERSION_BEFORE_5.1.0> sudo dnf versionlock add rt-thread

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2025-5865?

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

Is CVE-2025-5865 being exploited?

CVE-2025-5865 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-2025-5865 affect?

CVE-2025-5865 affects rt-thread. Severity is high (CVSS 8.0). 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 ar

How urgent is CVE-2025-5865?

Priority 48/100. 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-2025-5866 HIGH 8.0 MITIGATE A vulnerability classified as critical has been found in RT-Thread 5.1.0

References

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