CVE-2023-28772

Kernel memory overwrite via doubled hex output

Published Mar 23, 2023 · Updated May 5, 2025

Buffer overflow in the Linux kernel before 5.13.3 allows local users with high privileges to overwrite memory via seq_buf_putmem_hex. The function limits each chunk by the hexadecimal-output buffer size even though every input byte produces two output characters, allowing its output index to pass the destination boundary. Reaching the flawed function requires local high-privilege execution; public records do not document a reproducer or a specific post-overflow outcome.

CVSS severity6.7
Medium
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in the Linux kernel before 5.13.3 allows local users with high privileges to overwrite memory via seq_buf_putmem_hex. The function limits each chunk by the hexadecimal-output buffer size even though every input byte produces two output characters, allowing its output index to pass the destination boundary. Reaching the flawed function requires local high-privilege execution; public records do not document a reproducer or a specific post-overflow outcome.

The record

CVE
CVE-2023-28772
Published
Mar 23, 2023
Updated
May 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 23, 2023CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record 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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7CISA-ADPCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.7NVDCVSS:3.1/AV:L/AC:L/PR:H/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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer 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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