CVE-2025-65503: Use after free in endpoint destructors in Redboltz async_mqtt 10.2.5 allows local users to cause a denial of s

Routine

MEDIUM 5.5DOWNGRADE

CVE-2025-65503 is a medium-severity flaw (CVSS 5.5) affecting async mqtt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Use after free in endpoint destructors in Redboltz async_mqtt 10.2.5 allows local users to cause a denial of service via triggering SSL initialization failure that results in incorrect destruction order between io_context and endpoint objects.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-416
Published	2025-11-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: redboltz

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

Am I affected?

Timeline

2025-11-24 14:15 UTCPublished CVE record published
2026-06-17 09:55 UTCUpdated Record last modified

redboltz async mqtt DOWNGRADE

Affected: 10.2.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.2.5

1. Check installed version

apt-cache policy async-mqtt || rpm -q async-mqtt || async-mqtt --version

2. No fixed release: DOWNGRADE to a release before 10.2.5 (Debian / Ubuntu)

apt-cache madison async-mqtt sudo apt install async-mqtt=<VERSION_BEFORE_10.2.5> sudo apt-mark hold async-mqtt

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

dnf --showduplicates list async-mqtt sudo dnf downgrade async-mqtt-<VERSION_BEFORE_10.2.5> sudo dnf versionlock add async-mqtt

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-2025-65503?

async mqtt: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-65503 being exploited?

CVE-2025-65503 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-2025-65503 affect?

CVE-2025-65503 affects async mqtt. Severity is medium (CVSS 5.5). Use after free in endpoint destructors in Redboltz async_mqtt 10.2.5 allows local users to cause a denial of service via triggering SSL initialization failure that results in incorrect destruction order between io_context and endpoint objec

How urgent is CVE-2025-65503?

Priority 28/100. Public exploit reference

References

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