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Findings

RUSTSEC-2026-0365

Remote DoS through unchecked allocation in negentropy

Published Oct 14, 2026 · corrected/updated Oct 16, 2026 · evidence confidence medium

## Summary The crate is vulnerable to denial-of-service through an unchecked, peer-controlled ID count in reconciliation messages. With the feature enabled, which is the default configuration, a small malformed message can trigger an enormous memory allocation and terminate the application. ## Details When processing an range, the reconciliation parser uses the peer-provided ID count to reserve memory before checking whether the message contains the corresponding IDs: An attacker can declare an arbitrarily large count without supplying any IDs. The allocation occurs before the parser reaches the ID-reading loop, which would otherwise reject the truncated message. With Rust's default allocation-error behavior, a failed allocation aborts the process rather than unwinding. Consequently, cannot contain the failure. Both and reach the vulnerable parser. The patched versions validate the count against the remaining message length before allocating: ## Impact An unauthenticated remote attacker can terminate an application that exposes reconciliation to untrusted peers without additional validation. For example, a Nostr relay that forwards or reconciliation payloads to the vulnerable parser can be taken down by a single client message. Clients processing messages from malicious relays are also exposed. This specific vulnerability affects builds with the default feature enabled. Builds without use a and do not perform the vulnerable preallocation. A message-size limit alone does not prevent exploitation because the malicious payload can be only a few bytes long. ## Credit Discovered and fixed by **Alex Gleason** ( ).

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

RUSTSEC-2026-0365 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: negentropy (0.2.0 → 0.4.4). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.5. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 14, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    ## Summary The crate is vulnerable to denial-of-service through an unchecked, peer-controlled ID count in reconciliation messages. With the feature enabled, which is the default configuration, a small malformed message can trigger an enormous memory allocation and terminate the application. ## Details When processing an range, the reconciliation parser uses the peer-provided ID count to reserve me

  2. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    negentropy fixed in 0.4.4

  3. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    negentropy fixed in 0.4.4

  4. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    ## Summary The crate is vulnerable to denial-of-service through an unchecked, peer-controlled ID count in reconciliation messages. With the feature enabled, which is the default configuration, a small malformed message can trigger an enormous memory allocation and terminate the application. ## Details When processing an range, the reconciliation parser uses the peer-provided ID count to reserve me

Affected

  • crates.io negentropy0.2.0 → 0.4.4

Sources

References