Critical severity · published Feb 24, 2026
CVE-2026-1229
Incorrect calculation in CIRCL secp384r1 CombinedMult
9.8
CVSS
0.4%
EPSS
No
On KEV
Description
The CombinedMult function in the CIRCL ecc/p384 package (secp384r1 curve) produces an incorrect value for specific inputs. The issue is fixed by using complete addition formulas.
ECDH and ECDSA signing relying on this curve are not affected.
The bug was fixed in v1.6.3 https://github.com/cloudflare/circl/releases/tag/v1.6.3 .
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CI
CIRCL · Cloudflare
CIRCL up to version 1.6.2 before 1.6.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-1229
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-1229
Product
https://github.com/cloudflare/circl
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