CVE-2021-37592 [Critical] | Out-of-bounds Write in Suricata

CVE-2021-37592 is rated High Risk (65.7/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.55%). EPSS rose +1.39% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.16%	1.55%	+1.39%
2	2026-02-27	0.14%	0.16%	+0.02%
3	2025-11-21	—	0.14%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.16%

1.55%

+1.39%

2026-02-27

0.14%

0.16%

+0.02%

2025-11-21

—

0.14%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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: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.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/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:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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: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.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/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:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2021-37592

vendor	priority	summary	link
`alpine`	critical	CVE-2021-37592: 1 source package rows (suricata); 9 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 2.	https://security.alpinelinux.org/vuln/CVE-2021-37592
`debian`	not yet assigned	CVE-2021-37592 not yet assigned priority: Debian including 1 source packages (suricata), 4 status rows across 4 suites (bullseye, forky, sid, trixie): resolved 3, open 1.	https://security-tracker.debian.org/tracker/CVE-2021-37592
`ubuntu`	medium	CVE-2021-37592 medium priority: Ubuntu including 1 source packages (suricata), 12 status rows across 12 suites (bionic, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): released 9, needs-triage 2, ignored 1.	https://ubuntu.com/security/CVE-2021-37592

Affected software / configurations for CVE-2021-37592

Vendor	Product	Version	Raw CPE
oisf	suricata	< 5.0.8	cpe:2.3:a:oisf:suricata::::::::
oisf	suricata	>= 6.0.0, < 6.0.4	cpe:2.3:a:oisf:suricata::::::::

References for CVE-2021-37592

URL	Tags
https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942	Release Notes Vendor Advisory
https://github.com/OISF/suricata/releases	Release Notes Third Party Advisory
https://redmine.openinfosecfoundation.org/issues/4569	Permissions Required Third Party Advisory

URL

CVE-2021-37592

Exploit prediction scoring system (EPSS) score for CVE-2021-37592

Common vulnerability scoring system (CVSS) metrics for CVE-2021-37592

Weakness enumeration for CVE-2021-37592

OS Trackers for CVE-2021-37592

Affected software / configurations for CVE-2021-37592

References for CVE-2021-37592