How severe is CVE-2018-20187?

CVE-2018-20187 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2018-20187 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20187?

CVE-2018-20187 affects Botan Project Botan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-20187?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-20187 published?

CVE-2018-20187 was published on 2019-03-08 and last updated on 2026-06-17.

CVE-2018-20187

CVE-2018-20187 is a medium-severity vulnerability in Botan Project Botan with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-320.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-320
Affected product: Botan Project Botan
Published: 2019-03-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2018-20187?: 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.
How severe is CVE-2018-20187?: CVE-2018-20187 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2018-20187 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20187?: CVE-2018-20187 affects Botan Project Botan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-20187?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-20187 published?: CVE-2018-20187 was published on 2019-03-08 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:botan_project:botan:*:*:*:*:*:*:*:*

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