CVE-2021-22547

Heap memory access via unchecked calloc multiplication

Published May 4, 2021 · Updated Aug 3, 2024

Integer overflow in Google Cloud IoT Device SDK for Embedded C 1.0.2 and earlier allows local users to access adjacent heap memory. The __iotc_calloc function multiplies an attacker-controlled element count and size without checking for size_t overflow, then allocates and zeroes the wrapped, undersized length. A local low-privileged caller that can supply oversized allocation parameters can read or overwrite adjacent heap contents; no availability impact is reported.

CVSS severity6.3
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in Google Cloud IoT Device SDK for Embedded C 1.0.2 and earlier allows local users to access adjacent heap memory. The __iotc_calloc function multiplies an attacker-controlled element count and size without checking for size_t overflow, then allocates and zeroes the wrapped, undersized length. A local low-privileged caller that can supply oversized allocation parameters can read or overwrite adjacent heap contents; no availability impact is reported.

The record

CVE
CVE-2021-22547
Published
May 4, 2021
Updated
Aug 3, 2024
Vendor
Google
Product
Google Cloud IoT Device SDK for Embedded C
Classifications
CWE-120
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 4, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=1.0.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google · Google Cloud IoT Device SDK for Embedded Cversion=unspecified <=1.0.2

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.3Google LLCCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Overflow

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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