CVE-2026-33155: DeepDiff is a project focused on Deep Difference and search of any Python data

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-33155 is a high-severity flaw (CVSS 7.5) affecting deepdiff. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

DeepDiff is a project focused on Deep Difference and search of any Python data. From version 5.0.0 to before version 8.6.2, the pickle unpickler _RestrictedUnpickler validates which classes can be loaded but does not limit their constructor arguments. A few of the types in SAFE_TO_IMPORT have constructors that allocate memory proportional to their input (builtins.bytes, builtins.list, builtins.range). A 40-byte pickle payload can force 10+ GB of

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	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-400, CWE-770
Published	2026-03-20
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: qluster

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

Am I affected?

Timeline

2026-03-20 21:17 UTCPublished CVE record published
2026-06-17 10:37 UTCUpdated Record last modified

qluster deepdiff UPGRADE

Affected: >= 5.0.0 and < 8.6.2

Fixed in: 8.6.2

Safe to downgrade to: a release before 5.0.0

1. Check installed version

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

2. UPGRADE to 8.6.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade deepdiff

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 5.0.0 (Debian / Ubuntu)

apt-cache madison deepdiff sudo apt install deepdiff=<VERSION_BEFORE_5.0.0> sudo apt-mark hold deepdiff

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

dnf --showduplicates list deepdiff sudo dnf downgrade deepdiff-<VERSION_BEFORE_5.0.0> sudo dnf versionlock add deepdiff

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-2026-33155?

deepdiff: upgrade to 8.6.2. Exact commands for each OS are on this page.

Is CVE-2026-33155 being exploited?

CVE-2026-33155 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-2026-33155 affect?

CVE-2026-33155 affects deepdiff. Severity is high (CVSS 7.5). DeepDiff is a project focused on Deep Difference and search of any Python data. From version 5.0.0 to before version 8.6.2, the pickle unpickler _RestrictedUnpickler validates which classes can be loaded but does not limit their constructor

How urgent is CVE-2026-33155?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

References

← Back to latest CVEs