CVE-2024-11991: Motoko's incremental garbage collector is impacted by an uninitialized memory access bug, caused by incorrect

Routine

MEDIUM 5.6REMOTEUPGRADE

CVE-2024-11991 is a medium-severity flaw (CVSS 5.6) affecting motoko. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Motoko's incremental garbage collector is impacted by an uninitialized memory access bug, caused by incorrect use of write barriers in a few locations. This vulnerability could potentially allow unauthorized read or write access to a Canister's memory. However, exploiting this bug requires the Canister to enable the incremental garbage collector or enhanced orthogonal persistence, which are non-default features in Motoko.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.6 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-908
Published	2024-12-09
Last modified	2026-06-17

Publisher (CNA): DFINITY Foundation · Vendor: dfinity

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

Am I affected?

Timeline

2024-12-09 15:15 UTCPublished CVE record published
2026-06-17 06:58 UTCUpdated Record last modified

dfinity motoko UPGRADE

Affected: >= 0.9.0 and < 0.13.4

Fixed in: 0.13.4

Safe to downgrade to: a release before 0.9.0

1. Check installed version

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

2. UPGRADE to 0.13.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade motoko

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade motoko

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.9.0 (Debian / Ubuntu)

apt-cache madison motoko sudo apt install motoko=<VERSION_BEFORE_0.9.0> sudo apt-mark hold motoko

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list motoko sudo dnf downgrade motoko-<VERSION_BEFORE_0.9.0> sudo dnf versionlock add motoko

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-2024-11991?

motoko: upgrade to 0.13.4. Exact commands for each OS are on this page.

Is CVE-2024-11991 being exploited?

CVE-2024-11991 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-2024-11991 affect?

CVE-2024-11991 affects motoko. Severity is medium (CVSS 5.6). Motoko's incremental garbage collector is impacted by an uninitialized memory access bug, caused by incorrect use of write barriers in a few locations. This vulnerability could potentially allow unauthorized read or write access to a Canist

How urgent is CVE-2024-11991?

Priority 29/100. Remotely exploitable, no login, no user action

References

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