CyberSecBulletin
CVE-2022-39063NVD status: Modified

Open5GS: Use of Potentially Dangerous Function

Published Updated By the CyberSecBulletin desk

CVE-2022-39063 is a high-severity use of potentially dangerous function 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: <2.4.9. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.23% chance of exploitation within 30 days, higher than 69% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Open5GS you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Open5GSOpen5GS<2.4.9Not 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.

Official description

When Open5GS UPF receives a PFCP Session Establishment Request, it stores related values for building the PFCP Session Establishment Response. Once UPF receives a request, it gets the f_teid_len from incoming message, and then uses it to copy data from incoming message to struct f_teid without checking the maximum length. If the pdi.local_f_teid.len exceeds the maximum length of the struct of f_teid, the memcpy() overwrites the fields (e.g., f_teid_len) after f_teid in the pdr struct. After parsing the request, the UPF starts to build a response. The f_teid_len with its overwritten value is used as a length for memcpy(). A segmentation fault occurs, as a result of a memcpy(), if this overwritten value is large enough.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Potentially Dangerous Function

The product invokes a potentially dangerous function that could introduce a vulnerability if it is used incorrectly, but the function can also be used safely.

How developers prevent this class of flaw

  • Identify a list of prohibited API functions and prohibit developers from using these functions, providing safer alternatives. In some cases, automatic code analysis tools or the compiler can be instructed to spot use of prohibited functions, such as the banned.h include file from Microsoft's SDL.

More Use of Potentially Dangerous Function vulnerabilities (CWE-676)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Other vulnerabilities in Open5GS

All Open5GS vulnerabilities

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