CVE-2026-121506
Published:November 03, 2026
Updated:November 04, 2026
An out-of-bounds read and write in NTS client extension field parsing (extens_client_recv) in NTPsec before 1.2.5 allows a remote attacker who can send NTP server-mode replies to an NTS client to corrupt heap memory and crash ntpd, and, combined with the NTS-KE client out-of-bounds read fixed in 1.2.4, to bypass NTS authentication and set the client's time, via an NTS Authenticator and Encrypted Extension Fields field whose nonce length exceeds the field.
Affected Packages
https://gitlab.com/NTPsec/ntpsec.git (SCM_GIT):
Affected version(s) >=NTPsec_1_1_4 <NTPsec_1_2_5Fix Suggestion:
Update to version NTPsec_1_2_5Related Resources (5)
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Contact UsCVSS v4
Base Score:
8.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.4
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Out-of-bounds Write
EPSS
Base Score:
0.45