How severe is CVE-2026-40320?

No CVSS score has been assigned to CVE-2026-40320 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-40320?

CVE-2026-40320 affects the following packages: giskard-checks (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-40320?

Update giskard-checks to 1.0.2b1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40320 is resolved across your whole dependency graph.

How do I detect CVE-2026-40320 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for giskard-checks, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-40320 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-40320?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40320 can be triaged on real exposure rather than presence alone.

Is CVE-2026-40320 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-40320 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-40320?

CVE-2026-40320 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 4th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-40320?

CVE-2026-40320 is classified as CWE-1336 (CWE-1336). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-40320 published, and has it been updated?

CVE-2026-40320 was published on April 17, 2026 and was last updated on August 29, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-40320 — giskard-checks

CVE-2026-40320 is a CWE-1336 vulnerability in giskard-checks. A fix is available for giskard-checks — see the affected versions and patch details below.

Giskard has an Unsandboxed Jinja2 Template Rendering in ConformityCheck

Also known asGHSA-7xjm-g8f4-rp26PYSEC-2026-2488

Published

Apr 17, 2026

Updated

Aug 29, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40320.

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs4th percentile — riskier than 4% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐍giskard-checks

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The ConformityCheck class in giskard-checks rendered the rule parameter through Jinja2's default Template() constructor. Because the rule string is silently interpreted as a Jinja2 template, a developer may not realize that template expressions embedded in rule definitions are evaluated at runtime. In a scenario where check definitions are loaded from an untrusted source (e.g. a shared project file or externally contributed configuration), this could lead to arbitrary code execution.

giskard-checks is a local developer testing library with no network-facing service. Check definitions, including the rule parameter, are provided in application code or project configuration files and executed locally. Exploitation requires write access to a check definition and subsequent execution of the test suite by a developer.

However, the implicit template evaluation of the rule parameter is not obvious from the API surface. This hidden behavior increases the likelihood of a developer inadvertently passing untrusted input to it when integrating the library into a larger system.

Affected Component

conformity.py, line 59:

from jinja2 import Template
...
formatted_rule = Template(self.rule).render(trace=trace)

Affected Versions

giskard-checks < 1.0.2b1

Patched Version

giskard-checks >= 1.0.2b1 (template parsing removed from rule evaluation entirely)

Remediation

Upgrade to giskard-checks >= 1.0.2b1. The template rendering has been removed from rule evaluation.

Credit

Giskard-AI thanks @dhabaleshwar for identifying the unsandboxed template usage.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`giskard-checks`	all versions	1.0.2b1`pip install --upgrade 'giskard-checks==1.0.2b1'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for giskard-checks, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update giskard-checks to 1.0.2b1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40320 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40320 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-40320. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary The `ConformityCheck` class in `giskard-checks` rendered the `rule` parameter through Jinja2's default `Template()` constructor. Because the `rule` string is silently interpreted as a Jinja2 template, a developer may not realize that template expressions embedded in rule definitions are evaluated at runtime. In a scenario where check definitions are loaded from an untrusted source (e.g. a shared project file or externally contributed configuration), this could lead to arbitrary code execution. `giskard-checks` is a local developer testing library with no network-facing service. C

O3 Security · Impact-Aware SCA

Is CVE-2026-40320 in your dependencies?

O3 Security finds CVE-2026-40320 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works