CVE-2023-26555

Memory corruption via overlong Praecis response

Published Apr 11, 2023 · Updated Feb 11, 2025

Out-of-bounds write in the NTP Praecis driver before 4.2.8p16 allows physically proximate attackers to corrupt ntpd memory. The praecis_parse function does not bound a response line exceeding 100 bytes before it reaches an internal buffer. Exploitation requires physical access to a Praecis unit, maliciously altered firmware, and an ntpd configuration that uses the Praecis serial driver.

CVSS severity1.6
Low
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the NTP Praecis driver before 4.2.8p16 allows physically proximate attackers to corrupt ntpd memory. The praecis_parse function does not bound a response line exceeding 100 bytes before it reaches an internal buffer. Exploitation requires physical access to a Praecis unit, maliciously altered firmware, and an ntpd configuration that uses the Praecis serial driver.

The record

CVE
CVE-2023-26555
Published
Apr 11, 2023
Updated
Feb 11, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
physical
Privileges
admin

Timeline

How it unfolded

  1. Apr 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 11, 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 vectorphysical
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.6NTP ProjectCVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L
6.4NVDCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.4CISA-ADPCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
1.6NTP ProjectCVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:U/C:N/I:N/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.

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)
Vectorphysical
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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