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CVE-2015-1853

18
FAUCET Score

CVE-2015-1853 describes a denial-of-service vulnerability in chrony versions prior to 1.31.1, affecting authenticated symmetric NTP associations. An attacker with knowledge of NTP peering can send crafted NTP packets with random timestamps, preventing the chrony daemon from synchronizing. This vulnerability has a CVSS score of 6.5 (Medium), indicating a network-based attack with low complexity and high impact on availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.31.1CPE matchmatch criteria
cpe:2.3:a:tuxfamily:chrony:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.70%
Probability of exploitation in next 30 days
EPSS Percentile
74.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0170 is in the 88th percentile among its peer group of 21,958 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: chrony-0:2.1.1-1.el7
View patch

Vendor Advisories (1)

redhatCVE-2015-1853Moderate

chrony: authentication doesn't protect symmetric associations against DoS attacks

Apr 7, 2015

References

chrony.tuxfamily.org / News.html
Release NotesVendor Advisory
security.gentoo.org / glsa/201507-01
Third Party Advisory