CVE-2026-15791: A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory

Q: How do I fix CVE-2026-15791?

buildkit: upgrade to 0.31.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-15791 being exploited?

CVE-2026-15791 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-15791 affect?

CVE-2026-15791 affects buildkit. Severity is high (CVSS 7.5). A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory. The action that can normally be used to delete files inside the build container rootfs can escape into the real host temp direct

Q: How urgent is CVE-2026-15791?

Priority 40/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADE

CVE-2026-15791 is a high-severity flaw (CVSS 7.5) affecting buildkit. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory. The action that can normally be used to delete files inside the build container rootfs can escape into the real host temp directory.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-22
Published	2026-07-21
Last modified	2026-10-24

Publisher (CNA): Docker Inc. · Vendor: mobyproject

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-21 17:17 UTCPublished CVE record published
2026-10-24 19:10 UTCUpdated Record last modified

mobyproject buildkit UPGRADE

Affected: < 0.31.2

Fixed in: 0.31.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 0.31.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade buildkit

Note

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

Advisories and coverage

Official advisories

Amazon Linux 2023 ALAS: ALAS2023-2026-3140 (important): runfinch-finch 2026-09-29
Amazon Linux 2 ALAS: ALAS2DOCKER-2026-142 (important): runfinch-finch 2026-09-28

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-2026-15791?

buildkit: upgrade to 0.31.2. Exact commands for each OS are on this page.

Is CVE-2026-15791 being exploited?

CVE-2026-15791 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-2026-15791 affect?

CVE-2026-15791 affects buildkit. Severity is high (CVSS 7.5). A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory. The action that can normally be used to delete files inside the build container rootfs can escape into the real host temp direct

How urgent is CVE-2026-15791?

Priority 40/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-15788 HIGH 7.5 UPGRADE BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers does not detect NTFS di
CVE-2026-15789 HIGH 7.5 UPGRADE A custom client can produce such an upload request to the BuildKit daemon that files can escape from the Build
CVE-2026-15792 HIGH 7.5 UPGRADE A malicious BuildKit client or frontend could craft a request that could lead to BuildKit daemon crashing with
CVE-2026-15793 HIGH 7.5 UPGRADE BuildKit custom frontends or clients using the raw low-level API can set git.checkoutbundle=true when checking

References

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