CVE-2026-33155 DeepDiff has Memory Exhaustion DoS through SAFE_TO_IMPORT
An attacker can cause memory exhaustion and denial of service in applications using DeepDiff by providing a small malicious pickle payload.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33155?
CVE-2026-33155 is a high-severity denial of service vulnerability in seperman deepdiff, published on 20 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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 memory, which crashes applications that load delta objects or call pickle_load with untrusted data. This issue has been patched in version 8.6.2.
Which versions are affected by CVE-2026-33155?
3 open source packages ship an affected version, including deepdiff. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
deepdiff PyPI | From 5.0.0 | 8.6.2 |
deepdiff PyPI | From 5.0.0 | 8.6.2 |
deepdiff PyPI | From 5.0.0 | 8.6.2 |
Linux distribution packages (2)
python-deepdiff openSUSE:Leap 15.6 | All versions | 6.3.0-150600.3.6.1 |
python-deepdiff openSUSE:Tumbleweed | All versions | 8.6.2-1.1 |
Products include Qluster Deepdiff.
How do I fix CVE-2026-33155?
Upgrade deepdiff to 8.6.2 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33155 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33155 exists.
Sources
Also known as CLSA-2026-1781139163, DEBIAN-CVE-2026-33155, GHSA-54jj-px8x-5w5q, MINI-8g99-r865-r32p, PYSEC-2026-2445, SUSE-SU-2026:1094-1 and 2 more.