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CVE-2021-3571

24
FAUCET Score

CVE-2021-3571 describes a flaw in the linuxptp ptp4l program, specifically affecting little-endian architectures operating as a PTP transparent clock. A remote attacker can exploit this by sending a crafted one-step sync message, potentially leading to an information leak or system crash. This vulnerability carries a CVSS score of 7.1 (HIGH), indicating a low attack complexity and a significant impact on data confidentiality and system availability. While no active exploitation, public exploit code, or significant community discussion has been observed, affected products include various versions of fedoraproject, linuxptp_project, and redhat distributions.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.0.1CPE matchmatch criteria
cpe:2.3:a:linuxptp_project:linuxptp:*:*:*:*:*:*:*:*
>= 3.0, < 3.1.1CPE matchmatch criteria
cpe:2.3:a:linuxptp_project:linuxptp:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:-:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.1HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
4.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.90%
Probability of exploitation in next 30 days
EPSS Percentile
77.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0190 is in the 76th percentile among its peer group of 17,822 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

microsoftpatch availablevia msrc
Product: 19644-16823
microsoftpatch availablevia msrc
Product: cbl2 linuxptp on CBL Mariner 2.0
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: linuxptp-0:3.1.1-1.el8
View patch

Vendor Advisories (2)

microsoft2021-Jul/CVE-2021-3571Important

A flaw was found in the ptp4l program of the linuxptp package. When ptp4l is operating on a little-endian architecture as a PTP transparent clock, a remote attacker could send a crafted one-step sync message to cause an information leak or crash. The highest threat from this vulnerability is to data confidentiality and system availability. This flaw affects linuxptp versions before 3.1.1 and before 2.0.1.

Jul 13, 2021
redhatCVE-2021-3571Moderate

linuxptp: wrong length of one-step follow-up in transparent clock

Jul 5, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/RHRUVSDP673LXJ5HGIPQPWPIYUPWYQA7
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/VUBKTRCMJ6VKS7DIBSZQB4ATSKVCJYXJ