# Zcash Foundation Zebra resource exhaustion in P2P codec

Source: https://junglewise.ai/threats/zcash-foundation-zebra-resource-exhaustion-in-p2p-codec-189d566f  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-02. Updated: 2026-07-02  
License: CC BY 4.0 with a link back

Severity: low · CVSS 3.7 · Published 2026-07-02

Zebra, a Zcash node implementation, contains a flaw in how it handles incoming network connections. An attacker could send a small message that causes the software to reserve a large amount of virtual memory before completing a security handshake. While this could theoretically lead to resource exhaustion, existing security measures like connection limits and timeouts make a successful attack unlikely to impact service availability.

Technologies: [zebra-network (crates.io)](https://junglewise.ai/threats/technologies/zebra-network), [zebrad (crates.io)](https://junglewise.ai/threats/technologies/zebrad). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Low severity, with a CVSS score of 3.7, published 2 July 2026.

**Which products and versions are affected?** zebra-network (crates.io) <= 6.0.0; zebrad (crates.io) <= 4.4.1.

**Is there a fix for This vulnerability?** A patch was published on 2026-07-02. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run zebra-network (crates.io) or zebrad (crates.io) 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

A vulnerability exists in the P2P codec's Codec::decode() method in zebra-network. The component calls src.reserve() using an attacker-supplied body_len field from a 24-byte protocol header before the handshake completes. This allows a remote peer to reserve up to ~2 MiB of virtual buffer capacity per connection. The impact is mitigated because BytesMut::reserve() affects virtual address space rather than physical RAM until data is written, and Zebra employs per-IP connection limits and a 3-second handshake timeout. The issue is fixed in zebra-network 7.0.0 and zebrad 4.5.0 by deferring or capping reservations for pre-handshake messages.

## Affected products

- ZcashFoundation zebra-network <= 6.0.0
- ZcashFoundation zebrad <= 4.4.1

## Timeline

- 2026-05-29: disclosed: Reported via private GitHub Security Advisory submission
- 2026-07-02: advisory: GitHub Advisory published
- 2026-07-02: patched

## References

- [https://api.github.com/users/ouicate](https://api.github.com/users/ouicate)
- [https://github.com/ouicate](https://github.com/ouicate)
- [https://api.github.com/users/ouicate/gists%7B/gist_id%7D](https://api.github.com/users/ouicate/gists%7B/gist_id%7D)
- [https://api.github.com/users/ouicate/repos](https://api.github.com/users/ouicate/repos)
- [https://avatars.githubusercontent.com/u/250333441?v=4](https://avatars.githubusercontent.com/u/250333441?v=4)
- [https://api.github.com/users/ouicate/events%7B/privacy%7D](https://api.github.com/users/ouicate/events%7B/privacy%7D)

## Related threats

- [ZcashFoundation Zebra assertion panic in address book mempool update](https://junglewise.ai/threats/cve-2026-52829-zcashfoundation-zebra-assertion-panic-in-address-book-mempool)
- [ZcashFoundation Zebra process abort via repeated shielded transactions](https://junglewise.ai/threats/cve-2026-52739-zcashfoundation-zebra-process-abort-via-repeated-shielded)
- [ZcashFoundation Zebra denial of service via balance overflow in state writer](https://junglewise.ai/threats/cve-2026-52738-zcashfoundation-zebra-denial-of-service-via-balance-overflow-in)
- [Zcash Zebra sync restart poisoning via above-lookahead block](https://junglewise.ai/threats/cve-2026-52737-zcash-zebra-sync-restart-poisoning-via-above-lookahead-block)
- [ZcashFoundation Zebra block suppression via same-header body poisoning](https://junglewise.ai/threats/cve-2026-52736-zcashfoundation-zebra-block-suppression-via-same-header-body)