CVE-2026-86766: Snipe-IT 8.6.3 Race Condition via Consumable Checkout
Snipe-IT versions up to and including 8.6.3 contain a race condition (TOCTOU) in the consumable checkout API endpoint (POST /api/v1/consumables/{consumableid}/checkout). The requested quantity is validated against the number of remaining units before the database transaction begins, and the transaction then creates the checkout records without locking the consumable row or re-checking availability. An authenticated user with permission to check out consumables can submit concurrent checkout requests for the same consumable so that both requests pass the availability check and succeed, over-allocating stock and driving the remaining inventory negative (e.g., a consumable with 1 remaining unit ends at -1 after two concurrent 1-unit checkouts). The issue is fixed in 8.7.0, which re-fetches the parent row under lockForUpdate inside the transaction and re-validates availability.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Snipe-ITto a version that resolves this vulnerability.Fixed in 8.7.0 - Compensating control
If upgrading immediately, reduce the impact by preventing concurrent checkout requests for the same consumable (e.g., serialize requests per consumable_id at the application/load-balancer layer) to avoid TOCTOU over-allocation.
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker must be authenticated and have permission to check out consumables. They must be able to send concurrent requests to the consumable checkout API endpoint for the same item.
Are default deployments affected?
Any deployment running Snipe-IT 8.6.3 or an earlier version is affected if users are permitted to check out consumables. Exploitation does not require user interaction.
What is the impact of successful exploitation?
Concurrent checkout requests can both pass the pre-transaction availability check, causing stock to be over-allocated. Remaining inventory can be driven below zero.
What version fixes the issue?
Snipe-IT 8.7.0 fixes the issue by locking the consumable row and re-validating availability within the transaction.