CVE-2026-25793 HIGH

CVE-2026-25793: Nebula Has Possible Blocklist Bypass via ECDSA Signature Malleability

Vendor Slackhq
Product nebula
Weakness CWE-347
Published February 6, 2026
Last update February 9, 2026
View on NVD All CVEs

CVSS base score

7.6/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Nebula is a scalable overlay networking tool. In versions from 1.7.0 to 1.10.2, when using P256 certificates (which is not the default configuration), it is possible to evade a blocklist entry created against the fingerprint of a certificate by using ECDSA Signature Malleability to use a copy of the certificate with a different fingerprint. This issue has been patched in version 1.10.3.

Key dates

02Disclosure timeline

February 6, 2026 CVE published
February 9, 2026 Record updated