Improper Validation of Unsafe Equivalence in Input Affecting pydantic-ai-slim package, versions [2.0.0b1,2.44.0)[1.56.0,1.107.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published13 Oct 2026
- disclosed8 Oct 2026
- creditEurico Nicacio
Introduced: 8 Oct 2026
NewCVE-2026-107289 (opens in a new tab)How to fix?
Upgrade pydantic-ai-slim to version 2.44.0, 1.107.6 or higher.
Overview
pydantic-ai-slim is an Agent Framework / shim to use Pydantic with LLMs, slim package
Affected versions of this package are vulnerable to Improper Validation of Unsafe Equivalence in Input via IPv6 zone identifier handling in the _ssrf.py SSRF guard functions is_cloud_metadata_ip and is_private_ip. An attacker can supply an IPv6 address literal carrying a zone identifier (e.g. fd00:ec2::254%251) to bypass the blocklist checks, because Python's ipaddress module folds the zone identifier into address equality and hashing, causing the guarded address to compare unequal to the blocked entry. This allows requests to cloud metadata endpoints or private network addresses that should be denied.
Note: This is only exploitable if the application passes URLs that are, or could be, influenced by untrusted input into local network access.