CVE-2018-20187
An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery…
Does this matter?
Lower severity and a low EPSS score (1.52%). Track it; it rarely justifies an emergency change on its own.
Description
A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.
- CVSS 3.0
- 5.9 MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 1.52% probability · 75th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-320
- Affected
- botan project/botan
- Source
- cve@mitre.org
EPSS 1.5% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://botan.randombit.net/news.htmlRelease Notes, Vendor Advisory
- https://botan.randombit.net/security.htmlVendor Advisory
- https://github.com/crocs-muni/ECTesterNot Applicable, Third Party Advisory
- https://botan.randombit.net/news.htmlRelease Notes, Vendor Advisory
- https://botan.randombit.net/security.htmlVendor Advisory
- https://github.com/crocs-muni/ECTesterNot Applicable, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.