CVE-2015-1821
Heap-based buffer overflow in chrony before 1.31.1 allows remote authenticated users to cause a...
CVE-2015-1821 is a medium vulnerability (CVSS 6.5) in Tuxfamily Chrony, published April 12, 2015. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.41%, the 89th percentile. Fixed in chrony 1.30-2.
- Severity
- 6.5 MediumCVSS 2.0, NVD
- Exploit chance
- 3.41%EPSS, 89th percentile
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
1.30-2chrony +14 more
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.
Exploit likelihood
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
chronyDebian:12 | before 1.30-2 | 1.30-2 |
chronyDebian:13 | before 1.30-2 | 1.30-2 |
chronyDebian:14 | before 1.30-2 | 1.30-2 |
chronyDebian:6.0 From an advisory covering 3 CVEs | before 1.24-3+squeeze2, plus listed versions 1.24-31.24-3+squeeze1 | 1.24-3+squeeze2 |
chronyDebian:7 From an advisory covering 3 CVEs | before 1.24-3.1+deb7u3, plus listed versions 1.24-3.1+deb7u11.24-3.1+deb7u2 | 1.24-3.1+deb7u3 |
chronyMageia:4 From an advisory covering 3 CVEs | before 1.29.1-1.1.mga4 | 1.29.1-1.1.mga4 |
chronyRed Hat:enterprise_linux:7::client From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chrony-debuginfoRed Hat:enterprise_linux:7::client From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chronyRed Hat:enterprise_linux:7::computenode From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chrony-debuginfoRed Hat:enterprise_linux:7::computenode From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
Show 5 moreShow less
| Package | Affected | Fixed |
|---|---|---|
chronyRed Hat:enterprise_linux:7::server From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chrony-debuginfoRed Hat:enterprise_linux:7::server From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chronyRed Hat:enterprise_linux:7::workstation From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chrony-debuginfoRed Hat:enterprise_linux:7::workstation From an advisory covering 3 CVEs | before 0:2.1.1-1.el7 | 0:2.1.1-1.el7 |
chronyUbuntu:14.04:LTS | before 1.29-1ubuntu0.1, plus listed versions 1.26-41.29-1 | 1.29-1ubuntu0.1 |
What each source reports
NVD Score used
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.
- Record
CVE-2015-1821- CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-119
- Updated
- 2026-11-02
CVE ListNo score
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.
- Record
CVE-2015-1821- Updated
- 2026-11-02
EUVDEUVD-2015-1941No score
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.
- Record
EUVD-2015-1941- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cm73-xw9w-xqmmNo score
Heap-based buffer overflow in chrony before 1.31.1 allows remote authenticated users to cause a...
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.
- Record
GHSA-cm73-xw9w-xqmm- Weakness
- CWE-119
- Updated
- 2026-11-02
OSVNo score
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.
- Record
CVE-2015-1821- Updated
- 2026-11-02
OSVDEBIAN-CVE-2015-1821No score
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.
- Record
DEBIAN-CVE-2015-1821- Updated
- 2026-11-02
OSVMGASA-2015-0163No score
Updated chrony packages fix security vulnerabilities
Updated chrony package fixes security vulnerabilities:
Using particular address/subnet pairs when configuring access control would cause an invalid memory write. This could allow attackers to cause a denial of service (crash) or execute arbitrary code (CVE-2015-1821).
When allocating memory to save unacknowledged replies to authenticated command requests, a pointer would be left uninitialized, which could trigger an invalid memory write. This could allow attackers to cause a denial of service (crash) or execute arbitrary code (CVE-2015-1822).
When peering with other NTP hosts using authenticated symmetric association, the internal state variables would be updated before the MAC of the NTP messages was validated. This could allow a remote attacker to cause a denial of service by impeding synchronization between NTP peers (CVE-2015-1853).
- Record
MGASA-2015-0163- Updated
- 2026-11-02
OSVUBUNTU-CVE-2015-1821No score
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.
- Record
UBUNTU-CVE-2015-1821- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
References
debian.org/security/2015/dsa-3222
listengine.tuxfamily.org/chrony.tuxfamily.org/chrony-announce/2015/04/msg00002.html
securityfocus.com/bid/73955
oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
security.gentoo.org/glsa/201507-01
nvd.nist.gov/vuln/detail/CVE-2015-1821
Show 28 moreShow less
access.redhat.com/errata/RHSA-2015:2241
bugzilla.redhat.com/show_bug.cgi?id=1209631
github.com/advisories/GHSA-cm73-xw9w-xqmm
security-tracker.debian.org/tracker/CVE-2015-1821
advisories.mageia.org/MGASA-2015-0163.html
bugs.mageia.org/show_bug.cgi?id=15647
chrony.tuxfamily.org/News.html
security.access.redhat.com/data/csaf/v2/advisories/2015/rhsa-2015_2241.json
cve.org/CVERecord?id=CVE-2015-1821
ubuntu.com/security/CVE-2015-1821
git.tuxfamily.org/chrony/chrony.git/commit?h=1.31-security&id=cf19042ecb656b8afec0cc4906e7dd3ea9266ac8