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CVE-2021-42739

24
FAUCET Score

CVE-2021-42739 is a buffer overflow vulnerability in the Linux kernel's FireWire subsystem, specifically affecting versions through 5.14.13, due to improper bounds checking in the avc_ca_pmt function. This flaw impacts various distributions including Debian, Fedora, Oracle, and StarWind Software. With a CVSS score of 6.7 (Medium), it requires high privileges for local exploitation but can lead to high impact on confidentiality, integrity, and availability. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.14.13CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.44%
Probability of exploitation in next 30 days
EPSS Percentile
36.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0044 is in the 86th percentile among its peer group of 3,720 CVEs.

Social Chatter

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

Remediation

Patch Available

Vendor Patches (11)

microsoftpatch availablevia msrc
Product: cbl2 kernel 5.10.78.1-1 on CBL Mariner 2.0Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: 16885-16820Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: 16920-16823Fixed in: 5.10.78.1-1
microsoftpatch availablevia msrc
Product: cm1 kernel 5.10.78.1-1 on CBL Mariner 1.0Fixed in: 5.10.78.1-1
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-0:3.10.0-1160.53.1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt-0:3.10.0-1160.53.1.rt56.1193.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-372.9.1.rt7.166.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-372.9.1.el8
View patch
redhatworkaround availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel

Vendor Advisories (2)

microsoft2021-Oct/CVE-2021-42739Moderate

The firewire subsystem in the Linux kernel through 5.14.13 has a buffer overflow related to drivers/media/firewire/firedtv-avc.c and drivers/media/firewire/firedtv-ci.c because avc_ca_pmt mishandles bounds checking.

Oct 12, 2021
redhatCVE-2021-42739Moderate

kernel: Heap buffer overflow in firedtv driver

Apr 20, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingMitigationThird Party Advisory
git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit
lore.kernel.org / linux-media/YHaulytonFcW+lyZ%40mwanda
seclists.org / oss-sec/2021/q2/46
oracle.com / security-alerts/cpujul2022.html
PatchThird Party Advisory
starwindsoftware.com / security/sw-20220804-0001
Third Party Advisory