CVE-2021-31996Network attack vector

Process crash via duplicated ownership in merge

Published May 3, 2021 · Updated Aug 3, 2024

Double free in the algorithmica Rust crate through 0.1.8 allows attackers to crash a consuming process by sorting values with destructors. The merge_sort::merge() implementation duplicates and drops ownership of generic T values without guarding against repeated destruction. Exposure depends on a consuming application invoking the merge operation on a Vec whose element type implements Drop; the documented consequence is a process crash.

CVSS severity7.5
High
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in the algorithmica Rust crate through 0.1.8 allows attackers to crash a consuming process by sorting values with destructors. The merge_sort::merge() implementation duplicates and drops ownership of generic T values without guarding against repeated destruction. Exposure depends on a consuming application invoking the merge operation on a Vec whose element type implements Drop; the documented consequence is a process crash.

The record

CVE
CVE-2021-31996
Published
May 3, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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