CVE-2026-107289 pydantic CVE debrief

Who should care

Defenders responsible for Pydantic AI deployments, particularly in IPv6-enabled environments, should assess exposure and prioritize verification and remediation efforts. This includes reviewing Pydantic AI version and configuration, assessing the need for compensating controls, and monitoring for potential exploitation attempts.

Why it matters

Defenders should prioritize verifying exposure in IPv6-enabled environments using Pydantic AI versions 1.56.0 through 1.107.6 and 2.44.0, and assess the need for compensating controls.

• Potential exposure of cloud IAM credentials
• Bypass of cloud-metadata blocklist
• Required verification of Pydantic AI version and configuration
• Need for compensating controls in IPv6-enabled environments

Technical summary

Pydantic AI applications can bypass the cloud-metadata blocklist by appending an IPv6 zone identifier to an IPv6 metadata address when opt-in settings are enabled, potentially exposing cloud IAM credentials. This issue arises in IPv6-enabled environments using Pydantic AI versions 1.56.0 through 1.107.6 and 2.44.0. The vulnerability is related to SSRF (Server-Side Request Forgery) and cloud-metadata blocklist bypass via IPv6 zone identifier. The opt-in settings are disabled by default, but when enabled, they allow an attacker to influence URLs into local network access, leading to potential security risks.

Defensive priority

Defenders should prioritize verifying exposure in IPv6-enabled environments using Pydantic AI versions 1.56.0 through 1.107.6 and 2.44.0, and assess the need for compensating controls.

Recommended defensive actions

• Verify Pydantic AI version and configuration to determine exposure
• Assess the need for compensating controls in IPv6-enabled environments
• Monitor for potential exploitation attempts
• Update to Pydantic AI version 1.107.6 or 2.44.0
• Review relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and Pydantic AI source references provide details on the vulnerability, affected versions, and fixed versions. The vulnerability is related to SSRF (Server-Side Request Forgery) and cloud-metadata blocklist bypass via IPv6 zone identifier. Evidence limits and source grounding indicate that defenders should verify Pydantic AI version and configuration to determine exposure. The CVE record was published on 2026-10-08T15:20:18.056Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.