medium CVSS 6.8 EPSS 0.33%

CVE-2026-48782·Python vulnerability

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. In versions 1.56.0 through 1.101.0, 2.0.0b1, and 2.0.0b2, the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form that the previous fix, CVE-2026-46678, did not decode, exposing cloud IAM short-term credentials. The previous remediation decoded only IPv4-mapped IPv6, 6to4, and the NAT64 well-known prefix, so the metadata guarantee did not hold for the remaining transition forms: IPv4-compatible IPv6 (::a.b.c.d), the NAT64 RFC 8215 local-use prefix (64:ff9b:1::/48), operator-chosen NAT64 prefixes, and ISATAP. The IPv6 wrapper is then delivered to the underlying IPv4 metadata endpoint. This occurs when an application using Pydantic AI opts a URL into force_download='allow-local' (which disables the default block on private/internal IPs) and runs on a network that actually routes the affected IPv6 transition forms: NAT64-configured networks (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or networks with an ISATAP tunnel for ISATAP. A standard dual-stack cloud VM or container does not route these forms and is not affected in practice. The IPv4-compatible and Teredo variants are deprecated and addressed as defense-in-depth. This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580). This issue has been fixed in version 2.0.0b3.

Severity
medium
Software
Python
Fixed in
1.102.0
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 0.33% — higher than 25% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Affected versions

From: 1.56.0

Until: 1.102.0

Fixed in: 1.102.0

How to fix this CVE

Update Pydantic AI to version 1.102.0 or later to close a bypass in the cloud-metadata IP blocklist. This vulnerability allows attackers to access cloud IAM credentials on systems running Pydantic AI with force_download='allow-local' enabled and operating on networks with IPv6 transition forms (such as NAT64 or ISATAP). Ensure all instances using Pydantic AI are patched immediately to restore proper IP filtering.

sudo dnf update python3-pydantic-ai

Defensia detects this vulnerability

How to check if you are affected

  1. Check the installed Pydantic AI version: python3 -c "import pydantic_ai; print(pydantic_ai.__version__)"
  2. Verify if force_download='allow-local' is set in your application code: grep -r "force_download.*allow-local" /path/to/your/app/
  3. Review network configuration to confirm if IPv6 transition forms (NAT64, ISATAP) are in use: ip -6 route | grep -E "64:ff9b|::ffff|2001::|Teredo"
  4. Confirm the patch was applied by re-running: python3 -c "import pydantic_ai; print(pydantic_ai.__version__)" and verifying version >= 1.102.0

FAQ

What is CVE-2026-48782?

This vulnerability is an incomplete fix for a previous metadata endpoint bypass in Pydantic AI. Attackers can encode cloud-instance metadata IP addresses using additional IPv6 transition formats (IPv4-compatible IPv6, NAT64 RFC 8215 local-use prefix, ISATAP) to bypass the IP blocklist and retrieve short-term cloud IAM credentials on affected systems.

Is CVE-2026-48782 being actively exploited?

No, this vulnerability is not currently listed on CISA's Known Exploited Vulnerabilities catalog, and no public exploits have been released. However, the attack requires specific network conditions (NAT64 or ISATAP support) which limits but does not eliminate risk.

What versions of Pydantic AI are affected by CVE-2026-48782?

Pydantic AI versions 1.56.0 through 1.102.0 (inclusive) are vulnerable. This includes all 1.x releases in that range and early 2.0.0 beta versions (b1 and b2). Version 1.102.0 and later fixes the issue.

How do I check if my server is vulnerable to CVE-2026-48782?

Run: python3 -c "import pydantic_ai; print(pydantic_ai.__version__)" and compare against version 1.102.0. If your version is lower and your code uses force_download='allow-local', you are vulnerable. Additionally, check if your network supports IPv6 transition forms with: ip -6 route

Does Defensia detect CVE-2026-48782?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Pydantic AI is installed on a monitored server, CVE-2026-48782 will appear in your dashboard with remediation steps.

Related Python CVEs

CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-34938CVSS 10PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.
CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-26030CVSS 9.9Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-48782. Free for 1 server.

Get started free