CVE-2021-4186

Exp

Crash in the Gryphon dissector in Wireshark 3.4.0 to 3.4.10 allows denial of service via packet injection or crafted capture file

Published: 2021-12-30 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4186 is rated High Exploit Risk (68.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.15%). 1 public exploit reference(s) are indexed (Exploit-DB). 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-2021-4186

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

Exploit prediction scoring system (EPSS) score for CVE-2021-4186

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 2026-07-18 2.21% 2.15% -0.06%
2 2026-06-15 0.13% 2.21% +2.08%
3 2025-11-21 — 0.13% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4186

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L 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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 3.4 [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-2021-4186

OS Trackers for CVE-2021-4186

vendor priority summary link
alpine — CVE-2021-4186: 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-2021-4186
debian not yet assigned CVE-2021-4186 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-2021-4186
gentoo low CVE-2021-4186: 1 GLSA(s) (202210-04), 1 atom(s) (net-analyzer/wireshark); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-4186
redhat medium — https://access.redhat.com/security/cve/CVE-2021-4186
suse medium CVE-2021-4186 severity moderate: SUSE including 36 source package names (libwireshark15-3.6.20-150600.16.5, libwireshark15-3.6.8-150000.3.74.1, …), 153 product×package rows across 38 product lines (Image SLES15-SP3-SAP-Azure-LI-BYOS-Production, Image SLES15-SP3-SAP-Azure-VLI-BYOS-Production, … (38 product lines)): Fixed 100, Known Not Affected 53. https://www.suse.com/security/cve/CVE-2021-4186/
ubuntu medium CVE-2021-4186 medium priority: Ubuntu including 1 source packages (wireshark), 14 status rows across 14 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 7, ignored 5, released 2. https://ubuntu.com/security/CVE-2021-4186

Affected software / configurations for CVE-2021-4186

Vendor Product Version Raw CPE
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:*:*:*:*:*:*:*

References for CVE-2021-4186

URL Tags
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-4186.json Third Party Advisory
https://gitlab.com/wireshark/wireshark/-/issues/17737 Exploit Issue Tracking Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2EY2VFBU3YGGWI5BW4XKT3F37MYGEQUD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3FH2J57GDA2WMBS6J56F6QQRA6BXQQFZ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Q6XGBKWSQFCVYUN4ZK3O3NJIFP3OAFVT/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R5AEK3XTOIOGCGUILUFISMGX54YJXWGJ/
https://security.gentoo.org/glsa/202210-04 Third Party Advisory
https://www.wireshark.org/security/wnpa-sec-2021-16.html Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/09/msg00049.html
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