CVE-2021-43389

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-04 · updated 2026-06-17
Weakness: CWE-125

Description

An issue was discovered in the Linux kernel before 5.14.15. There is an array-index-out-of-bounds flaw in the detach_capi_ctr function in drivers/isdn/capi/kcapi.c.

Affected products

Debian Linux: 9.0, 10.0
Linux kernel: before 5.14.15 — fixed in 5.14.15
Oracle Communications Cloud Native Core Binding Support Function: 22.1.3
Oracle Communications Cloud Native Core Network Exposure Function: 22.1.1
Oracle Communications Cloud Native Core Policy: 22.2.0
Red Hat Enterprise Linux: 8.0

How to fix

Upgrade to a fixed version: Linux kernel 5.14.15. Check the vendor advisory for mitigations.

References

http://www.openwall.com/lists/oss-security/2021/11/05/1
https://bugzilla.redhat.com/show_bug.cgi?id=2013180
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.15
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1f3e2e97c003f80c4b087092b225c8787ff91e4d
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.html
https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
https://lore.kernel.org/netdev/CAFcO6XOvGQrRTaTkaJ0p3zR7y7nrAWD79r48=L_BbOyrK9X-vA%40mail.gmail.com/
https://seclists.org/oss-sec/2021/q4/39
https://www.debian.org/security/2022/dsa-5096
https://www.oracle.com/security-alerts/cpujul2022.html
http://www.openwall.com/lists/oss-security/2021/11/05/1
https://bugzilla.redhat.com/show_bug.cgi?id=2013180

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