CVE-2026-45758: Malicious code in guardrails-ai 0.10.1 (supply chain compromise)

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Only applies if your dependency tree includes guardrails-ai (PyPI) = 0.10.1, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

Guardrails AI is a Python framework that helps build AI applications. On May 11, 2026 at approximately 6:00 PM Pacific, an attacker published a malicious version of guardrails-ai (0.10.1) to PyPI. Aany user who installed guardrails-ai==0.10.1 from PyPI on May 11, 2026 may be affected. Security researchers identified the malicious package within approximately 2 hours of publication, and PyPI quarantined the repository. Based on our telemetry, Guardrails AI maintainers have observed no requests to Guardrails AI infrastructure originating from the malicious 0.10.1 version, and a review of system and access logs has produced no evidence of user data exfiltration through their systems. Users should upgrade to version 0.10.2 or downgrade to version 0.10.0, both of which are unaffected. Those who installed version 0.10.1 should rotate any credentials accessible from their machine (GitHub PATs, cloud provider keys, package registry tokens, API keys) and audit their GitHub account for unauthorized workflows or repositories.

From the GitHub advisory

Impact

On May 11, 2026 at approximately 6:00 PM Pacific, an attacker published a malicious version of guardrails-ai (0.10.1) to PyPI.

Affected: any user who installed guardrails-ai==0.10.1 from PyPI on May 11, 2026.

Security researchers identified the malicious package within approximately 2 hours of publication, and PyPI quarantined the repository. Based on our telemetry, we have observed no requests to Guardrails AI infrastructure originating from the malicious 0.10.1 version, and a review of system and access logs has produced no evidence of user data exfiltration through our systems.

For the full timeline, technical details, and remediation steps we have taken, see SECURITYADVISORY.md.

Weakness type: CWE-506.

Product: guardrails-ai (PyPI) · Assigned by: GitHub_M · Published: 2026-06-05

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.49% probability of exploitation activity in the next 30 days; percentile 41.

Timeline

• 2026-05-19 — GitHub-reviewed advisory GHSA-xmpw-2vmm-p4p6 published (critical)
• 2026-06-05 — CVE record published by GitHub_M
• 2026-06-08 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-xmpw-2vmm-p4p6 github.com
2. CVE.org record CVE-2026-45758 cve.org
3. NVD entry CVE-2026-45758 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com

Critical PyPI advisories · Today’s Security Digest