CVE-2021-39926

Exp

Buffer overflow in the Bluetooth HCI_ISO dissector in Wireshark 3.4.0 to 3.4.9 allows denial of service via packet injection or crafted capture file

Published: 2021-11-19 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-39926 is rated High Exploit Risk (82.8/100): CVSS High severity, with high exploitation likelihood (EPSS 7.50%, 94th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +6.56% 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-2021-39926

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

Exploit prediction scoring system (EPSS) score for CVE-2021-39926

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 0.94% 7.50% +6.56%
2 2025-12-11 0.96% 0.94% -0.02%
3 2025-11-21 — 0.96% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-39926

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-2021-39926

OS Trackers for CVE-2021-39926

vendor priority summary link
alpine high CVE-2021-39926: 1 source package rows (wireshark); 23 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 16. https://security.alpinelinux.org/vuln/CVE-2021-39926
debian not yet assigned CVE-2021-39926 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-2021-39926
gentoo low CVE-2021-39926: 1 GLSA(s) (202210-04), 1 atom(s) (net-analyzer/wireshark); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-39926
redhat medium — https://access.redhat.com/security/cve/CVE-2021-39926
suse medium CVE-2021-39926 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-2021-39926/
ubuntu medium CVE-2021-39926 medium 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, needs-triage 5, ignored 3, released 1. https://ubuntu.com/security/CVE-2021-39926

Affected software / configurations for CVE-2021-39926

Vendor Product Version Raw CPE
wireshark wireshark >= 3.4.0, <= 3.4.9 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 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-39926

cvelogic Threat Intelligence