Quick answers
- Is CVE-2026-88255 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-88255 being exploited in the wild.
- How severe is CVE-2026-88255?
- Informational severity, with a CVSS score of 6.5, published 16 September 2026.
- Which products and versions are affected?
- ZenHive Mpp 0.2.0 before 0.16.2.
- Is there a fix for CVE-2026-88255?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-88255 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-88255?
- Check whether you run ZenHive Mpp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in mpp.Methods.Tempo's reserve_hash_atomic/2 function, which keys deduplication by the raw transaction hex rather than a canonical form. The transaction deserializer accepts both ECDSA recovery-id encodings (v=27 and v=0), allowing a single signed transaction to be submitted twice with different recovery IDs, creating two distinct reserve keys that both pass the deduplication gate and reach the broadcast path. The credential replay store is deliberately carved out for Tempo, leaving only this reserve as the gate. A post-broadcast mark writes the canonical hash that the raw-keyed reserve never reads, so nodes may return duplicate Payment-Receipts for already-known transactions or trigger nonce-reuse rejections depending on node implementation.
Affected products
- ZenHive mpp 0.2.0 before 0.16.2
Timeline
- 2026-09-16: disclosed: CVE-2026-88255 published