VulnerabilityPublished 29 Jul 2026

CVE-2026-46678: pydantic-ai · Server-Side Request Forgery (SSRF)

Affects pydantic-aiSource CVE Database V5

Mentioned vulnerabilities

CVE-2026-25580

Not known to be exploited · CVSS 6.8 Medium : upgrade to 1.99.0 when convenient.

Data as of 27 Oct 2026, 17:11 UTC

CVSS 3.1 base score

6.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.99.0

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade pydantic-ai and pydantic-ai-slim to 1.99.0.

Affected software

Product	Affected	Fixed in
pydanticpydantic-ai	Affected >=1.56.0 <1.99.0	Fixed in 1.99.0
pydanticpydantic-ai-slim	Affected >=1.56.0 <1.99.0	Fixed in 1.99.0
PyPIpydantic-ai`pkg:pypi/pydantic-ai`Other threats	Affected >=1.56.0 <1.99.0	Fixed in 1.99.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade pydantic-ai to version 1.99.0 or later, where this vulnerability is fixed. Applications that do not explicitly enable force_download='allow-local' on URLs influenced by untrusted input are not affected. Bundled integrations that do not propagate force_download from external data or only download from developer-controlled URLs are also not vulnerable. Review application configurations to avoid enabling force_download='allow-local' on untrusted URLs.

Description

## Summary When an application using Pydantic AI opts a URL into `force_download='allow-local'` (which disables the default block on private/internal IPs), the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form (IPv4-mapped IPv6, 6to4, or NAT64). Dual-stack and translated networks route the IPv6 wrapper to the underlying IPv4 endpoint, exposing cloud IAM short-term credentials. This is an incomplete fix of [GHSA-2jrp-274c-jhv3](https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-2jrp-274c-jhv3) / [CVE-2026-25580](https://nvd.nist.gov/vuln/detail/CVE-2026-25580). The parent advisory's remediation guaranteed that "cloud metadata endpoints are always blocked, even with `allow-local`." That guarantee did not hold for IPv6-encoded forms of the metadata IPs. ## Severity Same impact metrics as the parent CVE, but materially narrower attack surface (AC:H instead of AC:L), because exploitation requires the application to have opted into `allow-local` on a URL influenced by untrusted input. ## Who Is Affected Applications are affected **only if** they explicitly opt for `FileUrl` (`ImageUrl`, `AudioUrl`, `VideoUrl`, `DocumentUrl`) into `force_download='allow-local'` on a URL that is, or could be, influenced by untrusted input. Applications are **not** affected if they use any of the bundled integrations to ingest user input, because they do not propagate `force_download` from external data: - `Agent.to_web` / `clai web` - `VercelAIAdapter` - `AGUIAdapter` / `Agent.to_ag_ui` Applications that only download from developer-controlled URLs are not affected. ## Remediation Upgrade to `1.99.0` or later. The cloud-metadata and private-IP blocklists now apply to IPv6 transition forms that route to a blocked IPv4 endpoint (IPv4-mapped IPv6, 6to4, and NAT64 well-known prefix). The blocklists have also been extended to cover additional IANA-reserved IPv4 and IPv6 special-purpose ranges. ## Workaround for Unpatched Versions Avoid passing `force_download='allow-local'` on any URL that could be influenced by untrusted input. If developers must, resolve the hostname themselves and validate the result against their own metadata blocklist — including IPv6-encoded forms — before constructing the `FileUrl`. ## Credits Reported by [j0hndo](mailto:dohyun4466@gmail.com).

Impact

Successful exploitation can lead to exposure of cloud IAM short-term credentials by bypassing the cloud-metadata IP blocklist through SSRF attacks using IPv6-encoded metadata IP addresses. This could allow an attacker to access sensitive cloud metadata services, potentially compromising cloud resource security. The vulnerability requires that the application explicitly opts into force_download='allow-local' on URLs influenced by untrusted input, limiting the scope of impact.

Summary

Pydantic AI, a Python framework for Generative AI applications, contains an SSRF vulnerability (CVE-2026-46678) in versions >=1.56.0 and <1.99.0. When an application explicitly sets force_download='allow-local' on a FileUrl-type parameter derived from untrusted input, the cloud-metadata IP blocklist can be bypassed by encoding the metadata IP in IPv6 transition formats such as IPv4-mapped IPv6, 6to4, or NAT64. This bypass exposes cloud IAM short-term credentials on networks supporting dual-stack or address translation. The vulnerability is an incomplete fix of CVE-2026-25580, which did not account for IPv6-encoded metadata IPs. Bundled integrations that do not propagate force_download from external data or that download only from developer-controlled URLs are not affected. The issue is resolved in pydantic-ai version 1.99.0.

CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Aug 2026, 17:53 UTC

WeaknessesCWE-918

Technical details

References

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