CVE-2026-22611VulnerabilityPublished 10 Jan 2026Updated 12 Jan 2026

CVE-2026-22611: aws-sdk-net · Improper Input Validation

Affects aws-sdk-netSource CVE Database V5

Not known to be exploited · CVSS 3.7 Low : upgrade to 4.0.3.3 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

3.7Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0.3.3

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade aws-sdk-net to 4.0.3.3.

Affected software

Product	Affected	Fixed in
awsaws-sdk-net	Affected >=4.0.0 <4.0.3.3	Fixed in 4.0.3.3

AI-suggested

European organizations should immediately upgrade all instances of AWS SDK for .NET to version 4.0.3.3 or later to ensure the region input validation flaw is remediated. Additionally, organizations should audit their environments to restrict access to systems running the SDK, minimizing the risk of attackers manipulating environment variables or configuration files. Implement strict access controls and monitoring on developer workstations, build servers, and deployment pipelines to detect unauthorized changes to SDK configuration parameters. Employ network segmentation and egress filtering to prevent API calls from being routed to unauthorized external hosts. Incorporate runtime application self-protection (RASP) or API gateway validation to detect and block anomalous API requests with invalid region parameters. Regularly review and update software dependencies to avoid running vulnerable SDK versions. Finally, conduct security awareness training for developers and operations teams about the risks of environment manipulation and the importance of timely patching.

Description

AWS SDK for .NET works with Amazon Web Services to help build scalable solutions with Amazon S3, Amazon DynamoDB, Amazon Glacier, and more. From versions 4.0.0 to before 4.0.3.3, Customer applications could be configured to improperly route AWS API calls to non-existent or non-AWS hosts. This notification is related to the use of specific values for the region input field when calling AWS services. An actor with access to the environment in which the SDK is used could set the region input field to an invalid value. This issue has been patched in version 4.0.3.3.

Impact

For European organizations, the impact of CVE-2026-22611 is primarily operational rather than directly compromising security. Misrouting AWS API calls could lead to application errors, failed service interactions, or potential denial of service conditions if API requests do not reach legitimate AWS endpoints. This could disrupt business-critical cloud services relying on AWS SDK for .NET, affecting availability and reliability of applications. However, since the vulnerability does not expose sensitive data or allow unauthorized actions, the confidentiality and integrity impact is minimal. Organizations with strict compliance requirements or those operating critical infrastructure may experience indirect impacts due to service interruptions. The risk is higher in environments where attackers can gain environment access, such as through compromised developer machines, CI/CD pipelines, or insider threats. European companies heavily dependent on AWS cloud services and using the affected SDK versions should prioritize patching to maintain operational stability and prevent potential exploitation scenarios that could degrade service quality.

Summary

CVE-2026-22611 is a vulnerability classified under CWE-20 (Improper Input Validation) found in the AWS SDK for .NET, specifically affecting versions from 4.0.0 to before 4.0.3.3. The SDK facilitates integration with AWS services such as Amazon S3, DynamoDB, and Glacier by allowing developers to specify a region parameter that directs API calls to the appropriate AWS service endpoints. The vulnerability arises because the SDK does not sufficiently validate the region input field, enabling an attacker with access to the environment where the SDK is running to supply invalid or malicious region values. This improper input can cause the SDK to route API requests to non-existent or non-AWS hosts, potentially leading to misdirected network traffic or denial of service for legitimate AWS API calls. The flaw does not inherently allow data leakage, unauthorized data modification, or service disruption beyond routing issues. Exploitation does not require authentication or user interaction but does require the attacker to have access to the environment where the SDK is used, such as through compromised credentials or insider threat. AWS addressed this vulnerability by releasing version 4.0.3.3 of the SDK, which implements proper validation of the region parameter to ensure only valid AWS regions are accepted, preventing the routing of API calls to unintended hosts. No public exploits or active exploitation have been reported to date.

CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/aws/aws-sdk-net/security/advisories/GHSA-9cvc-h2w8-phrp (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Jan 2026, 08:00 UTC

WeaknessesCWE-20

Technical details

References

Community reviews

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