CVE-2026-33540: Distribution is a toolkit to pack, ship, store, and deliver container content

Q: How do I fix CVE-2026-33540?

distribution: upgrade to 3.1.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-33540 being exploited?

CVE-2026-33540 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-2026-33540 affect?

CVE-2026-33540 affects distribution. Severity is high (CVSS 7.5). Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstrea

Q: How urgent is CVE-2026-33540?

Priority 41/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-33540 is a high-severity flaw (CVSS 7.5) affecting distribution. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstream registry. The realm URL from a bearer challenge is used without validating that it matches the upstream registry host. As a result, an attacker-controlled upstream (or an attacker with MitM position to the up

Why this priority

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

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	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-918
Published	2026-04-06
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: distribution project

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

Am I affected?

Timeline

2026-04-06 15:17 UTCPublished CVE record published
2026-06-17 10:37 UTCUpdated Record last modified

distribution project distribution UPGRADE

Affected: < 3.1.0

Fixed in: 3.1.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 3.1.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade distribution

Note

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

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-2026-33540?

distribution: upgrade to 3.1.0. Exact commands for each OS are on this page.

Is CVE-2026-33540 being exploited?

CVE-2026-33540 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-2026-33540 affect?

CVE-2026-33540 affects distribution. Severity is high (CVSS 7.5). Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstrea

How urgent is CVE-2026-33540?

Priority 41/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-35172 HIGH 7.5 UPGRADE Distribution is a toolkit to pack, ship, store, and deliver container content
CVE-2026-41888 MEDIUM 6.5 UPGRADE Distribution is a toolkit to pack, ship, store, and deliver container content

References

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