Open5GS Old AMF Discovery Fallback nnrf-handler.c amf_nnrf_try_old_amf_discovery_fallback use after free

published 2026-09-14 56 d ago modified 2026-09-15 55 d ago also EUVD-2026-77377

cvss: 8.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

A security flaw has been discovered in Open5GS up to 2.7.x. Affected is the function amf_nnrf_try_old_amf_discovery_fallback of the file src/amf/nnrf-handler.c of the component Old AMF Discovery Fallback. The manipulation of the argument discovery_option results in use after free. The attack may be performed from remote. The patch is identified as ddd683a35f8aaac2b7b9884a24cd53bddfc65238. Applying a patch is advised to resolve this issue.

Patch / fix

links 2

github.com/open5gs/open5gs@ddd683a commit
github.com/open5gs/open5gs#4698 pull request

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 55 d ago (2026-09-15)

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X
CNA	3.1	8.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA	3.0	8.3	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P/E:ND/RL:OF/RC:C
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/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
CNA	3.1	8.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
CNA	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

n/a Open5GS

Classification

Weakness

CWE-416 Use After Free
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

github.com /open5gs/open5gs/pull/4698
issue-tracking, patch
github.com /open5gs/open5gs/commit/ddd683a35f8aaac2b7b9884a24cd53bddfc65238
patch
vuldb.com /vuln/403249
vdb-entry, technical-description
vuldb.com /vuln/403249/cti
signature, permissions-required
vuldb.com /cve/CVE-2026-90707
third-party-advisory
vuldb.com /submit/918267
third-party-advisory
github.com /open5gs/open5gs/
product

Sources

CVE List CVE-2026-90707
NVD CVE-2026-90707

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary