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GHSA-4vgr-h27g-cf9p

SurrealDB: HTTP RPC Session Race Condition Allows Privilege Escalation

High crates.io
Severity
8.1 / 10
High · CVSS 3.1
Exploit chance (EPSS)
—
No score published
Known exploited
No
Not in CISA's catalog
Weakness
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Fix
3.1.0
Upgrade surrealdb to this version or later

Description

The HTTP /rpc endpoint has a time-of-check/time-of-use (TOCTOU) race condition on internal session state. When authenticated and unauthenticated requests are processed concurrently, the unauthenticated request can inherit the authenticated user's session and privileges. The /rpc endpoint is the primary interface used by all official SurrealDB SDKs.

The HTTP /rpc handler does not bind each incoming request to an isolated session context. Instead, concurrent requests share mutable authentication state. When an authenticated request sets the session context and an unauthenticated request races in before it is cleared, the unauthenticated request executes with the authenticated user's privileges.

The impact depends on the privilege level of the session that is hijacked. If a root or namespace-level user session is inherited, the attacker can read and modify any data, delete records, and create persistent namespace-level users. If a scoped record user session is inherited, the attacker is limited to that user's permissions.

The attack requires no credentials, tokens, or session knowledge — only the ability to send concurrent HTTP requests to the /rpc endpoint while legitimate authenticated traffic is active.

Impact

An unauthenticated attacker who can reach the /rpc endpoint can escalate privileges by racing against any active authenticated session. The severity of the impact depends on the permissions of the user whose session was hijacked. This could include escalation to root user of SurrealDB instance

Patches

Versions prior to SurrealDB v3.1.0 are vulnerable.

A patch has been introduced that replaces the shared default session with per-request session isolation. Every POST /rpc request now allocates a fresh, server-side UUID and runs entirely within that session's scope for the duration of the request. The session-map signatures across the RPC protocol have been changed from Option<Uuid> to Uuid so the "default session" can no longer be represented at the type level, preventing future regressions of the same shape.

Workarounds

There is no configuration-level mitigation that fully addresses this vulnerability. Network-level controls restricting access to the /rpc endpoint to trusted clients can reduce exposure.

Affected versions

crates.io

PackageVulnerableFixed in
surrealdb
< 3.1.0
3.1.0

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

surrealdb crates.io → 3.1.0

cargo
cargo update -p surrealdb --precise 3.1.0

Severity breakdown

CVSS 3.1 8.1

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

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Weakness

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How to prevent it
  • Architecture and Design: In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
  • Architecture and Design: Use thread-safe capabilities such as the data access abstraction in Spring.
  • Architecture and Design: Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
  • Implementation: When using multithreading and operating on shared variables, only use thread-safe functions.
  • Implementation: Use atomic operations on shared variables. Be wary of innocent-looking constructs such as "x++". This may appear atomic at the code layer, but it is actually non-atomic at the instruction layer, since it involves a read, followed by a computation, followed by a write.
  • Implementation: Use a mutex if available, but be sure to avoid related weaknesses such as CWE-412.
  • Implementation: Avoid double-checked locking (CWE-609) and other implementation errors that arise when trying to avoid the overhead of synchronization.
  • Implementation: Disable interrupts or signals over critical parts of the code, but also make sure that the code does not go into a large or infinite loop.
  • Implementation: Use the volatile type modifier for critical variables to avoid unexpected compiler optimization or reordering. This does not necessarily solve the synchronization problem, but it can help.
  • Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

References

Timeline

  1. Published
  2. Last updated by the source
AdvisorySeverityWhy it's related
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GHSA-97vg-427p-8hx5
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Medium Also affects surrealdb
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