CVE-2026-107292: Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header
Noroxi assessment
Priority: Monitor (action score 25/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
- Fixed version: pydantic-ai (PyPI) 1.107.5, 2.30.0; pydantic-ai-slim (PyPI) 1.107.5, 2.30.0.
Low priority for now. Upgrade to pydantic-ai (PyPI) 1.107.5, 2.30.0; pydantic-ai-slim (PyPI) 1.107.5, 2.30.0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 2.30.0, the Agent.to_web() and clai web development chat server does not validate the Host header, allowing a website visited by a developer to use DNS rebinding to reach a loopback-hosted agent as a same-origin service. The hostile page can read the served UI and submit chat requests that execute agent tools with the local process's privileges and credentials, causing data disclosure or unwanted side effects. Binding to localhost, Origin checks, and CSRF tokens do not prevent the same-origin DNS rebinding path. This issue is fixed in versions 1.107.5 and 2.30.0.
- Published
- Oct 8, 2026
- Updated
- Oct 14, 2026
- EPSS
- 0.1% · 2th percentile
- CWE
- CWE-346
Report tools
Action score
25
Low priority for now.
- CVSS
- 25 / 40 · 6.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 6.4
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| pydantic | pydantic ai | cpe:2.3:a:pydantic:pydantic_ai |
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
pydantic pydantic-ai
- >= 1.34.0, < 2.0.0b1, >= 2.0.0b1, < 2.30.0affected
pydantic pydantic-ai-slim
- >= 1.34.0, < 2.0.0b1, >= 2.0.0b1, < 2.30.0affected
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- pydantic pydantic ai1.34.0 and later · before 1.107.5
- pydantic pydantic ai2.0.0 and later · before 2.30.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| PyPI | pydantic-ai | from 1.34.0 · before 1.107.5 | 1.107.5 |
| PyPI | pydantic-ai | from 2.0.0b1 · before 2.30.0 | 2.30.0 |
| PyPI | pydantic-ai-slim | from 1.34.0 · before 1.107.5 | 1.107.5 |
| PyPI | pydantic-ai-slim | from 2.0.0b1 · before 2.30.0 | 2.30.0 |
Same product
pydantic: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-25580Pydantic AI Affected by Server-Side Request Forgery (SSRF) in URL Download Handling34Monitor
- CVE-2026-107295`pydantic-ai-slim` web UI `/api/chat` accepts browser-simple cross-origin requests that can trigger agent tool execution30Monitor
- CVE-2026-107286Pydantic AI: Concurrency-limited models can keep their slot when a streamed request ends early30Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-107290Oct 8, 2026 · Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`26Monitor
- ← EarlierCVE-2026-107291Oct 8, 2026 · Pydantic AI OpenTelemetry instrumentation: exception events on tool and agent run spans include content when `include_content=False`9Monitor
- Later →CVE-2026-107293Oct 8, 2026 · Pydantic AI OpenTelemetry instrumentation: retry prompt content is not redacted when `include_content=False`9Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| PyPI:pydantic-ai | 1.107.5 | Package registry (OSV) |
| PyPI:pydantic-ai | 2.30.0 | Package registry (OSV) |
| PyPI:pydantic-ai-slim | 1.107.5 | Package registry (OSV) |
| PyPI:pydantic-ai-slim | 2.30.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayNov 14, 2026+36 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Not on record for this CVE: researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- low · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- High
- Availability impact
- Low
Weakness class (CWE)
CWE-346 · Origin Validation ErrorCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- JSON Hijacking (aka JavaScript Hijacking)CAPEC-111likelihood: High · High
- Cache PoisoningCAPEC-141likelihood: High · High
- DNS Cache PoisoningCAPEC-142likelihood: High · High
- Exploit Script-Based APIsCAPEC-160Medium
- Exploitation of Trusted IdentifiersCAPEC-21likelihood: High · High
- Application API Message Manipulation via Man-in-the-MiddleCAPEC-384Low
- Transaction or Event Tampering via Application API ManipulationCAPEC-385Medium
- Application API Navigation RemappingCAPEC-386Medium
ATT&CK techniques
- Access Token ManipulationT1134
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Steal Application Access TokenT1528
- Steal Web Session CookieT1539
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Adversary-in-the-Middle: ARP Cache PoisoningT1557.002
- Compromise Infrastructure: DNS ServerT1584.002
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
- Exploit maturity— → none
For records you follow, these changes also arrive as notifications. →
References
Show all references (6 more)Show less
- github.com/pydantic/pydantic-ai/commit/871c7aeec5dfed2138655ccbccbf15c6d763bae7
- github.com/pydantic/pydantic-ai/pull/7437
- github.com/pydantic/pydantic-ai/pull/7438
- github.com/pydantic/pydantic-ai/releases/tag/v1.107.5
- github.com/pydantic/pydantic-ai/releases/tag/v2.30.0
- github.com/pydantic/pydantic-ai/security/advisories/GHSA-q2xc-rrxj-58x9
Vendor advisories and official records. Exploit/PoC links are deliberately left out.