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Vulnerability record · CVE-2018-20187 · published 8 March 2019

CVE-2018-20187: Botan project botan vulnerability

Botan Project · Botan

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.

5.9 CVSS 3.0 Medium EPSS 1.5% · top 26.3% CWE-320 · CWE-320
5.9CVSS 3.0 base score, v2 4.3
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

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/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://botan.randombit.net/news.html Release NotesVendor Advisory
https://botan.randombit.net/security.html Vendor Advisory
https://github.com/crocs-muni/ECTester Not ApplicableThird Party Advisory
https://botan.randombit.net/news.html Release NotesVendor Advisory
https://botan.randombit.net/security.html Vendor Advisory
https://github.com/crocs-muni/ECTester Not ApplicableThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-24115Botan project botan vulnerabilityIn Botan before 2.17.3, constant-time computations are not used for certain decoding and encoding operations (base32, base58, base64, and hex).EPSS 2.0%9.8CVE-2018-9127Botan project botan improper certificate validation vulnerabilityBotan 2.2.0 - 2.4.0 (fixed in 2.5.0) improperly handled wildcard certificates and could accept certain certificates as valid for hostnames when, unde…EPSS 0.93%9.8CVE-2017-2801Botan project botan out-of-bounds read vulnerabilityA programming error exists in a way Randombit Botan cryptographic library version 2.0.1 implements x500 string comparisons which could lead to certif…EPSS 1.3%9.8CVE-2016-6878Botan project botan improper input validation vulnerabilityThe Curve25519 code in botan before 1.11.31, on systems without a native 128-bit integer type, might allow attackers to have unspecified impact via v…EPSS 1.2%9.8CVE-2015-7826Botan project botan improper certificate validation vulnerabilitybotan 1.11.x before 1.11.22 improperly handles wildcard matching against hostnames, which might allow remote attackers to have unspecified impact via…EPSS 1.1%9.8CVE-2016-9132Botan project botan integer overflow vulnerabilityIn Botan 1.8.0 through 1.11.33, when decoding BER data an integer overflow could occur, which would cause an incorrect length field to be computed. S…EPSS 2.0%9.8CVE-2016-2196Botan project botan memory buffer overflow vulnerabilityHeap-based buffer overflow in the P-521 reduction function in Botan 1.11.x before 1.11.27 allows remote attackers to cause a denial of service (memor…EPSS 5.3%9.8CVE-2016-2195Botan project botan memory buffer overflow vulnerabilityInteger overflow in the PointGFp constructor in Botan before 1.10.11 and 1.11.x before 1.11.27 allows remote attackers to overwrite memory and possib…EPSS 6.7%

Source: NIST National Vulnerability Database (record CVE-2018-20187), CISA KEV, FIRST EPSS (scores of 2026-10-01). This page is refreshed as NVD updates the record.