CVE-2021-33590: GattLib 0.3-rc1 has a stack-based buffer over-read in get_device_path_from_mac in dbus/gattlib.c.

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-33590 is a critical-severity flaw (CVSS 9.8) affecting gattlib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GattLib 0.3-rc1 has a stack-based buffer over-read in get_device_path_from_mac in dbus/gattlib.c.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-125
Published	2021-05-27
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: labapart

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

Am I affected?

Timeline

2021-05-27 11:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

labapart gattlib DOWNGRADE

Affected: 0.3 rc1

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.3

1. Check installed version

apt-cache policy gattlib || rpm -q gattlib || gattlib --version

2. No fixed release: DOWNGRADE to a release before 0.3 (Debian / Ubuntu)

apt-cache madison gattlib sudo apt install gattlib=<VERSION_BEFORE_0.3> sudo apt-mark hold gattlib

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

dnf --showduplicates list gattlib sudo dnf downgrade gattlib-<VERSION_BEFORE_0.3> sudo dnf versionlock add gattlib

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-2021-33590?

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

Is CVE-2021-33590 being exploited?

CVE-2021-33590 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-2021-33590 affect?

CVE-2021-33590 affects gattlib. Severity is critical (CVSS 9.8). GattLib 0.3-rc1 has a stack-based buffer over-read in get_device_path_from_mac in dbus/gattlib.c.

How urgent is CVE-2021-33590?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-6498 HIGH 8.8 DOWNGRADE GattLib 0.2 has a stack-based buffer over-read in gattlib_connect in dbus/gattlib.c because strncpy is misused

References

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