CVE-2021-39928

Exp

NULL pointer exception in the IEEE 802.11 dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Published: 2021-11-18 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-39928 is rated High Exploit Risk (81.3/100): CVSS High severity, with high exploitation likelihood (EPSS 5.50%, 92th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +4.16% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2021-39928

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-39928

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 2026-06-15 1.34% 5.50% +4.16%
2 2026-01-14 1.46% 1.34% -0.11%
3 2025-12-28 — 1.46% —

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-39928

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-39928

OS Trackers for CVE-2021-39928

vendor priority summary link
alpine high CVE-2021-39928: 1 source package rows (wireshark); 35 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 28. https://security.alpinelinux.org/vuln/CVE-2021-39928
debian not yet assigned CVE-2021-39928 not yet assigned priority: Debian including 1 source packages (wireshark), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-39928
gentoo low CVE-2021-39928: 1 GLSA(s) (202210-04), 1 atom(s) (net-analyzer/wireshark); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-39928
redhat medium — https://access.redhat.com/security/cve/CVE-2021-39928
suse medium CVE-2021-39928 severity moderate: SUSE including 48 source package names (libwireshark14-3.4.10-1.1, libwireshark14-3.4.10-3.62.1, …), 135 product×package rows across 43 product lines (Image SLES15-SP3-SAP-Azure-LI-BYOS-Production, Image SLES15-SP3-SAP-Azure-VLI-BYOS-Production, … (43 product lines)): Fixed 82, Will Not Fix 53. https://www.suse.com/security/cve/CVE-2021-39928/
ubuntu low CVE-2021-39928 low priority: Ubuntu including 1 source packages (wireshark), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 6, ignored 3, needs-triage 3, needed 2, released 1. https://ubuntu.com/security/CVE-2021-39928

Affected software / configurations for CVE-2021-39928

Vendor Product Version Raw CPE
wireshark wireshark >= 3.2.0, < 3.2.18 cpe:2.3:a:wireshark:wireshark:*:*:*:*:*:*:*:*
wireshark wireshark >= 3.4.0, < 3.4.10 cpe:2.3:a:wireshark:wireshark:*:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2021-39928

cvelogic Threat Intelligence