How severe is CVE-2015-1821?

CVE-2015-1821 has a CVSS 2.0 base score of 6.5, rated medium severity.

Is CVE-2015-1821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-1821?

CVE-2015-1821 primarily affects Tuxfamily Chrony. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-1821?

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

When was CVE-2015-1821 published?

CVE-2015-1821 was published on 2015-04-16 and last updated on 2026-06-17.

CVE-2015-1821

CVE-2015-1821 is a medium-severity vulnerability in Tuxfamily Chrony with a CVSS 2.0 base score of 6.5. 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-119.

Key facts

Severity: Medium (CVSS 2.0 base score 6.5)
EPSS exploit prediction: 3% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Tuxfamily Chrony
Published: 2015-04-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2015-1821?: 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.
How severe is CVE-2015-1821?: CVE-2015-1821 has a CVSS 2.0 base score of 6.5, rated medium severity.
Is CVE-2015-1821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-1821?: CVE-2015-1821 primarily affects Tuxfamily Chrony. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-1821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-1821 published?: CVE-2015-1821 was published on 2015-04-16 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:tuxfamily:chrony:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*

More vulnerabilities in Tuxfamily Chrony

CVE-2016-1567 — High (CVSS 8.1): chrony before 1.31.2 and 2.x before 2.2.1 do not verify peer associations of symmetric keys when authenticating…
CVE-2015-1853 — Medium (CVSS 6.5): chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, which…
CVE-2015-1822 — Medium (CVSS 6.5): chrony before 1.31.1 does not initialize the last "next" pointer when saving unacknowledged replies to command…
CVE-2020-14367 — Medium (CVSS 6.0): A flaw was found in chrony versions before 3.5.1 when creating the PID file under the /var/run/chrony folder. The file…
CVE-2012-4503 — Medium (CVSS 5.0): cmdmon.c in Chrony before 1.29 allows remote attackers to obtain potentially sensitive information from stack memory…
CVE-2012-4502 — Medium (CVSS 5.0): Multiple integer overflows in pktlength.c in Chrony before 1.29 allow remote attackers to cause a denial of service…

All CVEs affecting Tuxfamily Chrony →

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