CVE-2026-5747: An out-of-bounds write issue in the virtio PCI transport in Firecracker 1.13.0 through 1.14.3 and 1.15.0 on x8

Routine

HIGH 7.5WATCHLISTUPGRADE

CVE-2026-5747 is a high-severity flaw (CVSS 7.5) affecting firecracker. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An out-of-bounds write issue in the virtio PCI transport in Firecracker 1.13.0 through 1.14.3 and 1.15.0 on x86_64 and aarch64 might allow a local guest user with root privileges to crash the Firecracker VMM process or potentially execute arbitrary code on the host via modification of virtio queue configuration registers after device activation. Achieving code execution on the host requires additional preconditions, such as the use of a custom gu

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Local
Attack complexity	High
Privileges needed	High
User interaction	None
EPSS exploit chance	0.3% (top 83%)
CISA exploited list	No
Weakness	CWE-369, CWE-787
Published	2026-04-08
Last modified	2026-07-24

Publisher (CNA): AMZN · Vendor: amazon

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-08 00:16 UTCPublished CVE record published
2026-07-24 09:10 UTCUpdated Record last modified

amazon firecracker UPGRADE

Affected: >= 1.13.0 and <= 1.14.3 · 1.15.0 · 1.15.0 dev

Fixed in: newer than 1.14.3

Safe to downgrade to: a release before 1.13.0

1. Check installed version

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

2. UPGRADE to newer than 1.14.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade firecracker

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 1.13.0 (Debian / Ubuntu)

apt-cache madison firecracker sudo apt install firecracker=<VERSION_BEFORE_1.13.0> sudo apt-mark hold firecracker

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

dnf --showduplicates list firecracker sudo dnf downgrade firecracker-<VERSION_BEFORE_1.13.0> sudo dnf versionlock add firecracker

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-2026-5747?

firecracker: upgrade to newer than 1.14.3. Exact commands for each OS are on this page.

Is CVE-2026-5747 being exploited?

CVE-2026-5747 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-2026-5747 affect?

CVE-2026-5747 affects firecracker. Severity is high (CVSS 7.5). An out-of-bounds write issue in the virtio PCI transport in Firecracker 1.13.0 through 1.14.3 and 1.15.0 on x86_64 and aarch64 might allow a local guest user with root privileges to crash the Firecracker VMM process or potentially execute a

How urgent is CVE-2026-5747?

Priority 36/100. High severity; On your watchlist

References

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