API Connect: Improper Restriction of Security Token Assignment
CVE-2026-16716 is a high-severity improper restriction of security token assignment vulnerability in API Connect from IBM, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected API Connect versions: 12.1.0.0 through 12.1.1.2; 10.0.8.0 through 10.0.8.12. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of API Connect you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on ibm.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| IBM | API Connect | 12.1.0.0 through 12.1.1.2; 10.0.8.0 through 10.0.8.12 | 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (us.ibm.com).
Official description
IBM API Connect 10.0.8.0 through 10.0.8.12 and 12.1.0.0 through 12.1.1.2 could allow a remote authenticated attacker to bypass security restrictions to access and modify sensitive information due to improper restriction of security token assignment.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Security Token Assignment
The System-On-A-Chip (SoC) implements a Security Token mechanism to differentiate what actions are allowed or disallowed when a transaction originates from an entity. However, the Security Tokens are improperly protected, such as improperly restricting the assignment to trusted components.
How developers prevent this class of flaw
- Since the Security Tokens are integral for the maintenance of security in an SoC, they need to be protected properly. Security Token assignment review checks for design inconsistency and common weaknesses. Security-Token definition and programming flow is tested in both pre-silicon and post-silicon testing.
More Improper Restriction of Security Token Assignment vulnerabilities (CWE-1259)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in API Connect
- 7.2 High severity
- 7.5 High severity
- 8.3 High severity
- 9.4 Critical severity
- 9.3 Critical severity
- 9.6 Critical severity
Recent Improper Restriction of Security Token Assignment vulnerabilities
- 8.2 High severity
- 8.1 High severity
- 7.2 High severity
- 7.5 High severity
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