CVE-2026-25793

Nebula Has Possible Blocklist Bypass via ECDSA Signature Malleability

CVSS 7.6 HIGHEPSS 0.1%CWE-347

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.

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

Affected products

slackhq · nebula

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References

https://github.com/slackhq/nebula/commit/f573e8a26695278f9d71587390fbfe0d0933aa21 https://github.com/slackhq/nebula/security/advisories/GHSA-69x3-g4r3-p962