Medium severity · published Mar 22, 2026
CVE-2026-4531
Free5GC AMF handler.go HandleRegistrationComplete denial of service
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
A weakness has been identified in Free5GC 4.1.0. Affected is the function HandleRegistrationComplete of the file internal/gmm/handler.go of the component AMF. Executing a manipulation can lead to denial of service. The attack may be performed from remote. This patch is called 52e9386401ce56ea773c5aa587d4cdf7d53da799. It is best practice to apply a patch to resolve this issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
Free5GC · Free5gc
4.1.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4531
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-4531
github.com
https://github.com/free5gc/amf/commit/52e9386401ce56ea773c5aa587d4cdf7d53da799
github.com
https://github.com/free5gc/amf/pull/198
github.com
https://github.com/free5gc/free5gc/
github.com
https://github.com/free5gc/free5gc/issues/792
vuldb.com
https://vuldb.com/?ctiid.352319
vuldb.com
https://vuldb.com/?id.352319
More from Free5GC
10.0
CVE-2026-44327
free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
10.0
CVE-2026-44329
free5GC: SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
10.0
CVE-2026-44330
free5GC: NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions
9.4
CVE-2026-44315
free5GC: NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions
9.4
CVE-2026-44326
free5GC: NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions