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Vulnerabilities

Vulnerability · RUSTSEC-2026-0365

Remote DoS through unchecked allocation in negentropy

Published Oct 14, 2026 · catalog updated Oct 16, 2026 · RustSec Rust

Open the advisory

Exploitation likelihood is not on this record for RUSTSEC-2026-0365. A missing EPSS score is not a low risk. Compare RustSec Rust with the linked advisory before you change production.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Advisory link
Affected products
crates.io negentropy

## 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** ( ).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • crates.io negentropy0.2.0 → 0.4.4

How to fix RUSTSEC-2026-0365

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for RUSTSEC-2026-0365. A missing EPSS score is not a low risk. Compare RustSec Rust with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 0.2.0 → 0.4.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

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

Sources

  • OpenSSF OSV / OSV ScannerPackage advisoryRUSTSEC-2026-0365

    Remote DoS through unchecked allocation in negentropy

    osv.dev
  • RustSec Advisory DBVendor advisoryRUSTSEC-2026-0365

    ## 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 a

    crates.io

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.