Open5GS: Improper Resource Shutdown or Release
CVE-2026-4240 is a high-severity improper resource shutdown or release vulnerability in Open5GS, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Open5GS versions: 2.7.0; 2.7.1; 2.7.2, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.62% chance of exploitation within 30 days, higher than 50% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Open5GS you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Open5GS | Open5GS | 2.7.0; 2.7.1; 2.7.2; 2.7.3; 2.7.4; 2.7.5; 2.7.6 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 5.3 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | CNA (vuldb.com) |
Official description
A vulnerability was determined in Open5GS up to 2.7.6. The affected element is the function smf_gx_cca_cb/smf_gy_cca_cb/smf_s6b_aaa_cb/smf_s6b_sta_cb of the component CCA Handler. This manipulation causes denial of service. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 2.7.7 is sufficient to fix this issue. Patch name: 80eb484a6ab32968e755e628b70d1a9c64f012ec. Upgrading the affected component is recommended.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Resource Shutdown or Release
The product does not release or incorrectly releases a resource before it is made available for re-use.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.
- Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
More Improper Resource Shutdown or Release vulnerabilities (CWE-404)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- github.com/open5gs/open5gs/issues/4343Issue Tracking, Third Party Advisory
- vuldb.com/?id.351182Third Party Advisory, VDB Entry
Technical write-ups (may include proof of concept)
- github.com/open5gs/open5gs/issues/4343#issue-4021871895Exploit, Issue Tracking, Third Party Advisory
- vuldb.com/?submit.771361Exploit, Third Party Advisory, VDB Entry
Other references
- github.com/open5gs/open5gs/Product
- vuldb.com/?ctiid.351182Permissions Required, VDB Entry
Other vulnerabilities in Open5GS
- 7.5 High severity
- 8.3 High severity
- 7.4 High severity
- 7.4 High severity
- 8.6 High severity
- 7.3 High severity
Recent Improper Resource Shutdown or Release vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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