CVE-2026-115419
Unintended disclosure of data element to wrong session in Strands Agents SDK A2A Server
The A2A server component in Amazon Strands Agents SDK for Python before 1.43.0 and Amazon Strands Agents SDK for TypeScript before 1.5.0 does not properly isolate conversation state between callers. An authenticated remote user could read other tenants' conversation history and add persistent instructions that alter model behavior for subsequent callers via HTTP requests to the A2A endpoint using a different context_id.
To mitigate this issue, users should upgrade to strands-agents 1.43.0 (Python) or @strands-agents/sdk 1.5.0 (TypeScript).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Unintended disclosure of data element to wrong session in Strands Agents SDK A2A Server
The A2A server component in Amazon Strands Agents SDK for Python before 1.43.0 and Amazon Strands Agents SDK for TypeScript before 1.5.0 does not properly isolate conversation state between callers. An authenticated remote user could read other tenants' conversation history and add persistent instructions that alter model behavior for subsequent callers via HTTP requests to the A2A endpoint using a different context_id.
To mitigate this issue, users should upgrade to strands-agents 1.43.0 (Python) or @strands-agents/sdk 1.5.0 (TypeScript).
- Record
CVE-2026-115419- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-488
- Updated
- 2026-11-02
EUVDEUVD-2026-108507
The A2A server component in Amazon Strands Agents SDK for Python before 1.43.0 and Amazon Strands Agents SDK for TypeScript before 1.5.0 does not properly isolate conversation state between callers. An authenticated remote user could read other tenants' conversation history and add persistent instructions that alter model behavior for subsequent callers via HTTP requests to the A2A endpoint using a different context_id.
To mitigate this issue, users should upgrade to strands-agents 1.43.0 (Python) or @strands-agents/sdk 1.5.0 (TypeScript).
- Record
EUVD-2026-108507- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4v6f-7vjh-6x4m
Strands Agents SDK: Exposure of data element to wrong session in the A2A Server
Summary
Strands Agents SDK is an open-source SDK, available for Python (strands-agents) and TypeScript (@strands-agents/sdk), for building and running AI agents. An issue exists where, under certain circumstances, the Agent2Agent (A2A) server shares conversation history across callers with different context_id values, allowing one caller to read and influence another caller's session.
Impact
The A2A server did not properly isolate conversation state between callers. In multi-tenant deployments, an authenticated remote user could access another caller's conversation history or influence model behavior for other callers (CWE-488: Unintended Disclosure of Data Element to Wrong Session). This affects any deployment where an A2A server is reachable by more than one user or tenant.
Impacted versions:
strands-agents (Python): all versions containing the multiagent.a2a module, < 1.43.0
@strands-agents/sdk (TypeScript): < 1.5.0
Patches
This issue has been addressed in strands-agents version 1.43.0 and @strands-agents/sdk version 1.5.0. The A2A server now uses an agent factory so conversation state is isolated per A2A context_id. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Workarounds
There is no workaround that fully addresses this issue in affected versions. Until you upgrade, do not expose an A2A server to more than one user or tenant. If multiple callers need access, run a separate A2A server instance for each user or tenant.
References
If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
- Record
GHSA-4v6f-7vjh-6x4m- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-488
- Updated
- 2026-11-02
NVD
The A2A server component in Amazon Strands Agents SDK for Python before 1.43.0 and Amazon Strands Agents SDK for TypeScript before 1.5.0 does not properly isolate conversation state between callers. An authenticated remote user could read other tenants' conversation history and add persistent instructions that alter model behavior for subsequent callers via HTTP requests to the A2A endpoint using a different context_id.
To mitigate this issue, users should upgrade to strands-agents 1.43.0 (Python) or @strands-agents/sdk 1.5.0 (TypeScript).
- Record
CVE-2026-115419- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-488
- Updated
- 2026-11-02
OSV
Unintended disclosure of data element to wrong session in Strands Agents SDK A2A Server
The A2A server component in Amazon Strands Agents SDK for Python before 1.43.0 and Amazon Strands Agents SDK for TypeScript before 1.5.0 does not properly isolate conversation state between callers. An authenticated remote user could read other tenants' conversation history and add persistent instructions that alter model behavior for subsequent callers via HTTP requests to the A2A endpoint using a different context_id.
To mitigate this issue, users should upgrade to strands-agents 1.43.0 (Python) or @strands-agents/sdk 1.5.0 (TypeScript).
- Record
CVE-2026-115419- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-488
- Updated
- 2026-11-02
OSVGHSA-4v6f-7vjh-6x4m
Strands Agents SDK: Exposure of data element to wrong session in the A2A Server
Summary
Strands Agents SDK is an open-source SDK, available for Python (strands-agents) and TypeScript (@strands-agents/sdk), for building and running AI agents. An issue exists where, under certain circumstances, the Agent2Agent (A2A) server shares conversation history across callers with different context_id values, allowing one caller to read and influence another caller's session.
Impact
The A2A server did not properly isolate conversation state between callers. In multi-tenant deployments, an authenticated remote user could access another caller's conversation history or influence model behavior for other callers (CWE-488: Unintended Disclosure of Data Element to Wrong Session). This affects any deployment where an A2A server is reachable by more than one user or tenant.
Impacted versions:
strands-agents (Python): all versions containing the multiagent.a2a module, < 1.43.0
@strands-agents/sdk (TypeScript): < 1.5.0
Patches
This issue has been addressed in strands-agents version 1.43.0 and @strands-agents/sdk version 1.5.0. The A2A server now uses an agent factory so conversation state is isolated per A2A context_id. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Workarounds
There is no workaround that fully addresses this issue in affected versions. Until you upgrade, do not expose an A2A server to more than one user or tenant. If multiple callers need access, run a separate A2A server instance for each user or tenant.
References
If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
- Record
GHSA-4v6f-7vjh-6x4m- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-488
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
strands-agentsPyPI |
before 1.43.0 | 1.43.0 |
@strands-agents/sdknpm |
before 1.5.0 | 1.5.0 |
strands-agentsPyPI |
before 1.43.0, plus listed versions 0.0.10.1.00.1.10.1.20.1.3 Show 45 moreShow less0.1.40.1.50.1.60.1.70.1.80.1.90.2.00.2.10.3.01.0.01.0.11.1.01.10.01.11.01.12.01.13.01.14.01.15.01.16.01.17.01.18.01.19.01.2.01.20.01.21.01.22.01.23.01.24.01.25.01.26.01.27.01.28.01.29.01.3.01.30.01.31.01.32.01.33.01.34.01.34.11.35.01.36.01.37.01.38.01.39.0 |
1.43.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-115419 is a high vulnerability (CVSS 8.6) in Aws Strands-agents, published October 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in strands-agents 1.43.0.
References
pypi.org/project/strands-agents/1.43.0
npmjs.com/package/@strands-agents/sdk/v/1.5.0
aws.amazon.com/security/security-bulletins/2026-146-aws
github.com/strands-agents/harness-sdk/security/advisories/GHSA-4v6f-7vjh-6x4m
nvd.nist.gov/vuln/detail/CVE-2026-115419
Show 9 moreShow less
Left out here: 11 versions. The JSON record has them.