CVE-2021-29937

Undefined behavior via premature vector initialization

Published Apr 1, 2021 · Updated Aug 3, 2024

Memory-safety error in the telemetry crate through 0.1.2 causes undefined behavior when misc::vec_with_size receives a panicking Clone. The function sets the vector length before initializing its elements, so unwinding from value.clone() would drop uninitialized entries. RustSec withdrew the advisory because public functions instantiate this private generic function only with primitive Clone types, whose clone operations cannot panic, so safe dependent code cannot trigger the behavior.

CVSS severity9.8
Critical
EPSS probability1.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-safety error in the telemetry crate through 0.1.2 causes undefined behavior when misc::vec_with_size receives a panicking Clone. The function sets the vector length before initializing its elements, so unwinding from value.clone() would drop uninitialized entries. RustSec withdrew the advisory because public functions instantiate this private generic function only with primitive Clone types, whose clone operations cannot panic, so safe dependent code cannot trigger the behavior.

The record

CVE
CVE-2021-29937
Published
Apr 1, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-908
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 1, 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

9.8RustSecCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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