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Fencer Intel
high 7.1

CVE-2021-3571 json

A flaw was found in the ptp4l program of the linuxptp package.

published 5y ago modified 4mo ago also EUVD-2021-26881

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

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.

Patch / fix

  • linuxptp_project linuxptp 2.0.1, 3.1.1
  • linuxptp Debian 14, Debian 13, Debian 12 3.1-2.1

debian advisories DEBIAN-CVE-2021-3571

  • linuxptp RHEL 8 3.1.1-1.el8

red hat advisories RHSA-2021:4321

  • linuxptp AlmaLinux 8 3.1.1-1.el8

almalinux advisories ALSA-2021:4321

  • linuxptp Rocky Linux 8 3.1.1-1.el8

rocky linux advisories RLSA-2021:4321

Is CVE-2021-3571 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3571 updated cvss 7.1

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

  • Red Hat Enterprise Linux 7 linuxptp
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) linuxptp 3.1.1-1.el8
    fixed: vendor fix RHSA-2021:4321
  • Red Hat Enterprise Linux 6 linuxptp Red Hat Enterprise Linux 9 linuxptp
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.90% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:N/A:P

Affected products

  • n/a linuxptp

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-125 Out-of-bounds Read

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.