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Vulnerability · Published Nov 3, 2026 · Assigned by GitLab

CVE-2026-121505Out-of-bounds Read in NTPsec

Low 3.7

In plain English

A low-severity out-of-bounds read in NTPsec from NTPsec. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.3%top 78.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

An out-of-bounds read in the NTS-KE client response parser (nts_client_process_response_core) in NTPsec before 1.2.4 allows a malicious NTS-KE server to read the client's stack memory, including pointers that defeat ASLR, which the client then sends in cleartext as NTS cookies, via an NTS-KE record whose declared length exceeds the data received.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12ntpsecno fix listedDEBIAN-CVE-2026-121505
Debian:13ntpsecno fix listedDEBIAN-CVE-2026-121505
Debian:14ntpsec1.2.4+dfsg-1DEBIAN-CVE-2026-121505
Ubuntu:22.04:LTSntpsecno fix listedUBUNTU-CVE-2026-121505
Ubuntu:24.04:LTSntpsecno fix listedUBUNTU-CVE-2026-121505
Ubuntu:26.04:LTSntpsecno fix listedUBUNTU-CVE-2026-121505
Ubuntu:26.10ntpsecno fix listedUBUNTU-CVE-2026-121505

Affected products (as reported)

VendorProductVersions
NTPsec NTPsec 1.1.4 – before 1.2.4

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References