CVE-2018-20187
mediumpriority · track · 25EPSS 0.015 · 75 %ileEUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (12)
External citations — patches, advisories, analysis.
- https://botan.randombit.net/Patchcnnvd
- https://botan.randombit.net/news.htmlcnnvd
- https://botan.randombit.net/security.htmlcnnvd
- https://github.com/crocs-muni/ECTestercnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2018-20187cnnvd
- https://vigilance.fr/vulnerability/Botan-information-disclosure-via-ECC-Generation-28556cnnvd
- https://botan.randombit.net/news.htmlenisa_euvd
- https://botan.randombit.net/security.htmlenisa_euvd
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