CVE-2021-37625 [High] | Denial of Service in Skytable

Skytable is an open source NoSQL database. In versions prior to 0.6.4 an incorrect check of return value of the accept function in the run-loop for a TCP socket/TLS socket/TCP+TLS multi-socket causes an early exit from the run loop that should continue infinitely unless terminated by a local user, effectively causing the whole database server to shut down. This has severe impact and can be used to easily cause DoS attacks without the need to use much bandwidth. The attack vectors include using an incomplete TLS connection for example by not providing the certificate for the connection and using a specially crafted TCP packet that triggers the application layer backoff algorithm.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2024-05-31	0.16%	0.11%	-0.05%
2	2024-04-20	0.10%	0.16%	+0.06%
3	2023-03-07	—	0.10%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2024-05-31

0.16%

0.11%

-0.05%

2024-04-20

0.10%

0.16%

+0.06%

2023-03-07

—

0.10%

—

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]

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]

Affected software / configurations for CVE-2021-37625

Vendor	Product	Version	Raw CPE
skytable	skytable	0.1.0	cpe:2.3:a:skytable:skytable:0.1.0:::::::*
skytable	skytable	0.2.0	cpe:2.3:a:skytable:skytable:0.2.0:::::::*
skytable	skytable	0.3.0	cpe:2.3:a:skytable:skytable:0.3.0:::::::*
skytable	skytable	0.3.1	cpe:2.3:a:skytable:skytable:0.3.1:::::::*
skytable	skytable	0.3.2	cpe:2.3:a:skytable:skytable:0.3.2:::::::*
skytable	skytable	0.4.0	cpe:2.3:a:skytable:skytable:0.4.0:::::::*
skytable	skytable	0.4.1	cpe:2.3:a:skytable:skytable:0.4.1:::::::*
skytable	skytable	0.4.2	cpe:2.3:a:skytable:skytable:0.4.2:::::::*
skytable	skytable	0.4.3	cpe:2.3:a:skytable:skytable:0.4.3:::::::*
skytable	skytable	0.4.4	cpe:2.3:a:skytable:skytable:0.4.4:::::::*
skytable	skytable	0.4.5	cpe:2.3:a:skytable:skytable:0.4.5:::::::*
skytable	skytable	0.5.0	cpe:2.3:a:skytable:skytable:0.5.0:::::::*
skytable	skytable	0.5.1	cpe:2.3:a:skytable:skytable:0.5.1:::::::*
skytable	skytable	0.5.2	cpe:2.3:a:skytable:skytable:0.5.2:::::::*
skytable	skytable	0.6.0	cpe:2.3:a:skytable:skytable:0.6.0:::::::*
skytable	skytable	0.6.1	cpe:2.3:a:skytable:skytable:0.6.1:::::::*
skytable	skytable	0.6.2	cpe:2.3:a:skytable:skytable:0.6.2:::::::*
skytable	skytable	0.6.3	cpe:2.3:a:skytable:skytable:0.6.3:::::::*

References for CVE-2021-37625

URL	Tags
https://github.com/skytable/skytable/commit/bb19d024ea1e5e0c9a3d75a9ee58ff03c70c7e5d	Patch Third Party Advisory
https://github.com/skytable/skytable/security/advisories/GHSA-q27r-h25m-hcc7	Third Party Advisory
https://security.skytable.io/ve/s/00002.html	Patch Vendor Advisory

URL

CVE-2021-37625 | Incorrect Check of Function Return Value in Skytable

Exploit prediction scoring system (EPSS) score for CVE-2021-37625

Common vulnerability scoring system (CVSS) metrics for CVE-2021-37625

Weakness enumeration for CVE-2021-37625

Affected software / configurations for CVE-2021-37625

References for CVE-2021-37625