CVE-2021-4028

A flaw in the Linux kernel's implementation of RDMA communications manager listener code allowed an attacker with local access to setup a socket to listen on a high port allowing for a list element to be used after free. Given the ability to execute code, a local attacker could leverage this use-after-free to crash the system or possibly escalate privileges on the system.

Published: 2022-08-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4028 is rated Low Risk (35.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-4028

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.10% 0.04% -0.06%
2 2025-11-18 0.02% 0.10% +0.07%
3 2025-03-30 — 0.02% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4028

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2021-4028

OS Trackers for CVE-2021-4028

vendor priority summary link
debian not yet assigned CVE-2021-4028 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-4028
redhat high — https://access.redhat.com/security/cve/CVE-2021-4028
suse high CVE-2021-4028 severity important: SUSE including 63 source package names (bpftool-3.10.0-1160.62.1.el7, bpftool-4.18.0-348.23.1.el8_5, …), 350 product×package rows across 65 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (65 product lines)): Known Not Affected 245, Fixed 105. https://www.suse.com/security/cve/CVE-2021-4028/
ubuntu medium CVE-2021-4028 medium priority: Ubuntu including 122 source packages (linux, linux-allwinner, …), 1314 status rows across 12 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 967, not-affected 167, released 118, ignored 62. https://ubuntu.com/security/CVE-2021-4028

Affected software / configurations for CVE-2021-4028

Vendor Product Version Raw CPE
linux linux_kernel >= 5.10, < 5.10.71 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.14.10 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
suse linux_enterprise 15.0 cpe:2.3:o:suse:linux_enterprise:15.0:sp3:*:*:*:*:*:*
suse linux_enterprise 15.0 cpe:2.3:o:suse:linux_enterprise:15.0:sp4:*:*:*:*:*:*

References for CVE-2021-4028

cvelogic Threat Intelligence