CVE-2021-31162Public exploit

Application crash via panic-unsafe Vec iterator cleanup

Published Apr 14, 2021 · Updated Aug 3, 2024

Double free in the Rust standard library before 1.52.0 allows attackers to crash applications through a panicking element destructor. Vec::from_iter's in-place specialization drops remaining elements before advancing its source pointer, so unwinding after a Drop panic processes an already freed element again. Reachability requires an application to collect from a Vec iterator through that specialization while a remaining element's destructor panics; the published proof of concept ends in allocator-detected double free and process termination.

CVSS severity9.8
Critical
EPSS probability2.89%
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 Rust standard library before 1.52.0 allows attackers to crash applications through a panicking element destructor. Vec::from_iter's in-place specialization drops remaining elements before advancing its source pointer, so unwinding after a Drop panic processes an already freed element again. Reachability requires an application to collect from a Vec iterator through that specialization while a remaining element's destructor panics; the published proof of concept ends in allocator-detected double free and process termination.

The record

CVE
CVE-2021-31162
Published
Apr 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 14, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-415Double Free

Public exploit references

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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