CVE-2021-3438

Local privilege escalation via unchecked IOCTL length

Published May 20, 2021 · Updated Aug 3, 2024

Classic buffer overflow in HP and Samsung Windows printer drivers allows local users to elevate privileges through a driver IOCTL. The SSPORT.SYS handler passes a user-controlled IOCTL length to strncpy without validating it against the destination buffer, causing a kernel buffer overrun. The loaded driver is reachable by low-privileged local users without an attached printer; the researchers did not weaponize the flaw independently.

CVSS severity8.8
High
EPSS probability2.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Classic buffer overflow in HP and Samsung Windows printer drivers allows local users to elevate privileges through a driver IOCTL. The SSPORT.SYS handler passes a user-controlled IOCTL length to strncpy without validating it against the destination buffer, causing a kernel buffer overrun. The loaded driver is reachable by low-privileged local users without an attached printer; the researchers did not weaponize the flaw independently.

The record

CVE
CVE-2021-3438
Published
May 20, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 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 vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8HPCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
4.6NIST NVDAV:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 Copy without Checking Size of Input ('Classic Buffer Overflow')
T1068Exploitation for Privilege Escalation

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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