Is CVE-2015-3405 in the CISA KEV catalog?

No. CVE-2015-3405 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-3405?

CVE-2015-3405 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2015-3405?

CVE-2015-3405 has an EPSS score of 5.29% (92th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-3405?

Upgrade ntp on debian 11 to 1:4.2.6.p5+dfsg-7 or later.

CVE & CISA-KEV Catalog

CVE-2015-3405

HIGHEPSS 92th pctl

7.5

CVSS v3

NVD

Description

ntp-keygen in ntp 4.2.8px before 4.2.8p2-RC2 and 4.3.x before 4.3.12 does not generate MD5 keys with sufficient entropy on big endian machines when the lowest order byte of the temp variable is between 0x20 and 0x7f and not #, which might allow remote attackers to obtain the value of generated MD5 keys via a brute force attack with the 93 possible keys.

CWE-331

How to fix

Remediation Available

ntpDebian

Fixed in:1:4.2.6.p5+dfsg-7CVE-2015-3405

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

5.29%probability of exploitation in 30 days

92ndpercentile

High risk: more likely to be exploited than 92% of all known CVEs.

References

Patch1

bugzilla.redhat.com

Vendor Advisory2

Third-Party Advisory8

Other references3

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-13.