GHSA-hqxq-hwqf-wg83

Summary

A transaction integrity flaw allows an authenticated tenant user to soft-delete synced non-manual transactions through the transaction update endpoint, despite the application explicitly blocking deletion of those transactions via the normal DELETE path. This bypass undermines the intended protection for imported transaction records and allows protected transactions to be hidden from normal views.

Details

The issue affects the transaction update path for synced transactions associated with non-manual links. The intended policy is clearly enforced in the DELETE handler: deletion of synced transactions for non-manual links is rejected with an error indicating that such transactions cannot be deleted.

However, the PUT update path still accepts a client-controlled full Transaction object and persists fields that should be server-managed, including deletedAt. The update logic appears to restrict only selected fields, which leaves deletedAt attacker-controllable.

Verified behavior on the same synced transaction showed:

• DELETE was denied with the expected protection error for non-manual links
• PUT with a user-supplied deletedAt value succeeded and returned 200 OK
• a subsequent transaction list no longer showed the transaction
• GET by transaction ID still returned the record with deletedAt populated

This demonstrates a policy bypass: although the server explicitly defines synced transactions on non-manual links as non-deletable through the dedicated delete route, the same outcome can still be achieved through the update route by setting the soft-delete field directly.

The vulnerability is therefore not a simple UI inconsistency. It is a server-side authorization and integrity flaw caused by trusting a client-supplied full transaction object and failing to protect sensitive server-managed fields from modification.

PoC

The issue can be reproduced by identifying a synced transaction on a non-manual link, confirming that the normal DELETE route rejects deletion, then submitting an update request that sets the transaction’s deletedAt field. The transaction will then disappear from normal listing views even though direct retrieval still shows the record as soft-deleted.

Impact

• Type: Authorization bypass / integrity violation
• Who is impacted: Authenticated tenant users and any deployment relying on synced transaction immutability for non-manual links
• Security impact: Attackers can hide or effectively delete protected imported transactions that should not be deletable, compromising transaction history, bookkeeping integrity, and trust in audit-relevant server-managed fields
• Attack preconditions: The attacker must be authenticated and able to access a synced transaction within their own tenant/account scope