CVE-2023-33974 [High] | Denial of Service in Riot

RIOT-OS, an operating system for Internet of Things (IoT) devices, contains a network stack with the ability to process 6LoWPAN frames. In versions 2023.01 and prior, an attacker can send multiple crafted frames to the device to trigger a race condition. The race condition invalidates assumptions about the program state and leads to an invalid memory access resulting in denial of service. This issue is patched in pull request 19679. There are no known workarounds.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	1.26%	0.71%	-0.55%
2	2026-05-31	0.18%	1.26%	+1.08%
3	2025-11-21	—	0.18%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

1.26%

0.71%

-0.55%

2026-05-31

0.18%

1.26%

+1.08%

2025-11-21

—

0.18%

—

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]
5.9	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/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:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. 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.	2.2	3.6	[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]

5.9

3.1

MEDIUM

CVSS:3.1/AV:N/AC:H/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:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.

2.2

3.6

[email protected]

Affected software / configurations for CVE-2023-33974

Vendor	Product	Version	Raw CPE
riot-os	riot	<= 2023.01	cpe:2.3:o:riot-os:riot::::::::

References for CVE-2023-33974

URL	Tags
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c#L1717	Product
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c#L509	Product
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c#L617	Product
https://github.com/RIOT-OS/RIOT/blob/master/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c#L1586	Product
https://github.com/RIOT-OS/RIOT/blob/master/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c#L404	Product
https://github.com/RIOT-OS/RIOT/commit/31c6191f6196f1a05c9765cffeadba868e3b0723	Patch
https://github.com/RIOT-OS/RIOT/pull/19679	Patch
https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-8m3w-mphf-wxm8	Vendor Advisory

URL

CVE-2023-33974 | RIOT-OS vulnerable to Race Condition in SFR Timeout

Exploit prediction scoring system (EPSS) score for CVE-2023-33974

Common vulnerability scoring system (CVSS) metrics for CVE-2023-33974

Weakness enumeration for CVE-2023-33974

Affected software / configurations for CVE-2023-33974

References for CVE-2023-33974