# hickory-proto vulnerable to CPU exhaustion during message encoding due to O(n²) name compression

Source: https://junglewise.ai/threats/hickory-proto-vulnerable-to-cpu-exhaustion-during-message-encoding-due-a5904f49  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-07  
License: CC BY 4.0 with a link back

Severity: medium · CVSS 4 · Published 2026-05-07

hickory-proto vulnerable to CPU exhaustion during message encoding due to O(n²) name compression

Technologies: [hickory-proto (crates.io)](https://junglewise.ai/threats/technologies/hickory-proto). 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?** Medium severity, with a CVSS score of 4, published 7 May 2026.

**Which products and versions are affected?** hickory-proto (crates.io) SEMVER:introduced=0.3.1,fixed=0.26.1.

**Is there a fix for This vulnerability?** Yes. hickory-proto (crates.io): upgrade to 0.26.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected?** Check whether you run hickory-proto (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.

## How to fix

- hickory-proto (crates.io): upgrade to 0.26.1 or later

  ```sh
  cargo update -p hickory-proto
  ```


## Affected products

- hickory-proto (crates.io) SEMVER:introduced=0.3.1,fixed=0.26.1

## Related threats

- [hickory-proto: NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses](https://junglewise.ai/threats/hickory-proto-nsec3-closest-encloser-proof-validation-enters-unbounded-e7dc6c28)
- [RUSTSEC-2026-0118 - NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses](https://junglewise.ai/threats/rustsec-2026-0118-nsec3-closest-encloser-proof-validation-enters-1c6355b8)
- [RUSTSEC-2026-0119 - CPU exhaustion during message encoding due to O(n²) name compression](https://junglewise.ai/threats/rustsec-2026-0119-cpu-exhaustion-during-message-encoding-due-to-o-n-817a4c82)
- [Hickory DNS failure to verify self-signed RRSIG for DNSKEYs](https://junglewise.ai/threats/hickory-dns-failure-to-verify-self-signed-rrsig-for-dnskeys-8cc3be51)
- [Hickory DNS's DNSSEC validation may accept broken authentication chains](https://junglewise.ai/threats/cve-2025-25188-hickory-dns-s-dnssec-validation-may-accept-broken-authentication)