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CVE-2025-66646

24
FAUCET Score

CVE-2025-66646 is a denial-of-service vulnerability affecting RIOT OS v2025.07 and earlier, an open-source microcontroller operating system for IoT devices. The flaw exists in the IPv6 fragmentation reassembly implementation, where a specially crafted fragmented IPv6 packet can lead to a NULL pointer dereference, causing the OS to crash. With a CVSS score of 7.5 (High), this vulnerability can be exploited remotely with low attack complexity, requiring no user interaction or privileges. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2025.10CPE matchmatch criteria
cpe:2.3:o:riot-os:riot:*:*:*:*:*:*:*:*
2025.10CPE matchmatch criteria
cpe:2.3:o:riot-os:riot:2025.10:rc1:*:*:*:*:*:*
2025.10CPE matchmatch criteria
cpe:2.3:o:riot-os:riot:2025.10:rc2:*:*:*:*:*:*
2025.10CPE matchmatch criteria
cpe:2.3:o:riot-os:riot:2025.10:rc3:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

1.7LOW

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
LOW
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
UNREPORTED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.59%
Probability of exploitation in next 30 days
EPSS Percentile
44.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0059 is in the 22nd percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c
Product
github.com / RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/pktbuf_static/gnrc_pktbuf_static.c
Product
github.com / RIOT-OS/RIOT/releases/tag/2025.10
Release Notes
github.com / RIOT-OS/RIOT/security/advisories/GHSA-v8gx-q9m6-5xm9
ExploitPatchVendor Advisory
github.com / user-attachments/files/23903992/reproducer_1.zip
Exploit