CVE-2020-28895Network attack vector

Memory corruption via overflowing calloc size calculation

Published Feb 3, 2021 · Updated Aug 4, 2024

Integer overflow in calloc in Wind River VxWorks 6.9 allows remote attackers to corrupt memory through a crafted allocation request. The allocator multiplies the element count by the element size without preventing integer wraparound, then returns a block smaller than the caller-requested buffer; subsequent writes overrun that allocation. Exploitation requires a reachable code path that passes attacker-controlled allocation dimensions to calloc, with consequences confined to memory corruption in the affected process or device.

CVSS severity7.3
High
EPSS probability1.57%
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 calloc in Wind River VxWorks 6.9 allows remote attackers to corrupt memory through a crafted allocation request. The allocator multiplies the element count by the element size without preventing integer wraparound, then returns a block smaller than the caller-requested buffer; subsequent writes overrun that allocation. Exploitation requires a reachable code path that passes attacker-controlled allocation dimensions to calloc, with consequences confined to memory corruption in the affected process or device.

The record

CVE
CVE-2020-28895
Published
Feb 3, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, CWE-190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

7.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-190Integer Overflow or Wraparound

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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