Is CVE-2015-1821 in the CISA KEV catalog?

No. CVE-2015-1821 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-1821?

CVE-2015-1821 has a CVSS v2 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2015-1821?

CVE-2015-1821 has an EPSS score of 3.44% (88th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-1821?

Upgrade chrony on debian 11 to 1.30-2 or later.

CVE & CISA-KEV Catalog

CVE-2015-1821

MEDIUMEPSS 88th pctl

6.5

CVSS v2

NVD

Description

Heap-based buffer overflow in chrony before 1.31.1 allows remote authenticated users to cause a denial of service (chronyd crash) or possibly execute arbitrary code by configuring the (1) NTP or (2) cmdmon access with a subnet size that is indivisible by four and an address with a nonzero bit in the subnet remainder.

CWE-119Buffer Overflow

How to fix

Remediation Available

chronyDebian

Fixed in:1.30-2CVE-2015-1821

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

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

3.44%probability of exploitation in 30 days

88thpercentile

Elevated risk: more likely to be exploited than 88% of all known CVEs.

References

Patch1

listengine.tuxfamily.org

Other references4

Related Vulnerabilities

Other CWE-119 (Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-4966	Critical	9.4	100%	KEV + Ransom	Fix
CVE-2017-11882	High	7.8	100%	KEV + Ransom	-
CVE-2020-0796	Critical	10.0	100%	KEV + Ransom	-
CVE-2008-4250	Critical	9.8	99%	KEV	-
CVE-2017-15944	Critical	9.8	98%	KEV	Fix
CVE-2015-0014	High	10.0	97%	-	-

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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 2026-05-06.