bedrock-agentcore 1.18.1: Improper Neutralization of Argument Delimiters in a Command
CVE-2026-16796 is a high-severity improper neutralization of argument delimiters in a command vulnerability in bedrock-agentcore 1.18.1 from AWS, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. The record lists version 1.18.1 as the first without the flaw, so updating bedrock-agentcore 1.18.1 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.73% chance of exploitation within 30 days, higher than 55% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update bedrock-agentcore 1.18.1 to 1.18.1 or a later version.
- Read the advisory on aws.amazon.com for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| AWS | bedrock-agentcore 1.18.1 | before 1.18.1 | 1.18.1 |
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
- RequiredA user must take an action such as opening a file or link.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.4 | High | CNA |
| CVSS 3.1 | 7.3 | High | CNA |
Official description
Improper neutralization of argument delimiters in the install_packages() method in AWS Bedrock AgentCore Python SDK before 1.18.1 might allow a remote authenticated user to execute arbitrary commands within the Code Interpreter sandbox via crafted package name arguments. To mitigate this issue, users should upgrade to the patched version 1.18.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Argument Delimiters in a Command
The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
How developers prevent this class of flaw
- Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application. Perform input validation at well-defined interfaces.
- Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
- When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
More Improper Neutralization of Argument Delimiters in a Command vulnerabilities (CWE-88)
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
Advisories
Other references
Recent Improper Neutralization of Argument Delimiters in a Command vulnerabilities
- 9.9 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
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