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Security advisory

Strands A2A: keep each user’s conversations separate

An authenticated user may read or influence another user’s conversations on an affected shared A2A server. Update the Strands SDK and verify session isolation.

Disclosed Oct 22, 2026Updated Oct 25, 2026Record reviewed Oct 25, 2026 UTCLatest evidence check Oct 25, 2026 UTC

Incident record
Product / service	Strands Agents SDK for Python, Strands Agents SDK for TypeScriptStrands Agents
CVE	CVE-2026-115419
Exploitation evidence	Exploitation not established
Access required	Account access required
Vendor severity	8.1CVSS 3.1
Severity by CVE	CVE-2026-115419 · 8.1 · CVSS 3.1
Fix / response	Fix availableAffected versions and fixes

Technical overview

The affected A2A server can share conversation state across callers. The advisory provides no complete workaround: restrict each server to one user or tenant until updated. The fix isolates state by context_id.

The reviewed advisories do not establish exploitation in the wild. This record covers the SDK’s A2A server, not every application built with Strands.

Affected systems and fixes

Product	Affected	Fixed release / action
strands-agents (Python)	Versions containing multiagent.a2a before 1.43.0	1.43.0
@strands-agents/sdk (TypeScript)	Before 1.5.0	1.5.0

Confirm the running version against the vendor advisory, including any distribution backports.

CISA KEV evidence

Catalog 2026.10.23 · Checked Oct 25, 2026 UTC

No matching CVE appears in the reviewed catalog snapshot. This does not establish that exploitation has not occurred. Check the incident sources and vendor guidance.

Supporting evidence

Known attacks and forecast

FIRST EPSS · Checked 2026-10-25 13:14 UTC

Affected product	What we know about attacks
Strands Agents SDK for Python / Strands Agents SDK for TypeScriptCVE-2026-115419 Forecast & technical details for CVE-2026-115419 0.34% estimated chance this vulnerability will be used in attacks over the next 30 days. This is not the chance of an attack on your organization. FIRST EPSS · Score dated Oct 24, 2026Higher than 26.24% of scored vulnerabilities.Unchanged since Oct 23, 2026.View source data	Real-world attacks not confirmedThis does not mean the vulnerability is safe to ignore.

Affected product

What we know about attacks

Strands Agents SDK for Python / Strands Agents SDK for TypeScriptCVE-2026-115419

Forecast & technical details

0.34% estimated chance this vulnerability will be used in attacks over the next 30 days. This is not the chance of an attack on your organization.

FIRST EPSS · Score dated Oct 24, 2026Higher than 26.24% of scored vulnerabilities.Unchanged since Oct 23, 2026.View source data

Real-world attacks not confirmedThis does not mean the vulnerability is safe to ignore.

A forecast is not evidence of an attack. Confirmed attacks take priority even when the forecast is low. How the forecast works

Strands Agents

Response checklist

0 of 3 complete

Identify shared A2A serversCheck SDK versions and whether different users or tenants reach the same server.Update both deployments and forksInstall the fixed SDK and incorporate the fix in derivative code. Until updated, use a separate server instance per user or tenant.Verify boundaries before reopening accessOktsec recommends testing with synthetic accounts and conversations to confirm that one user cannot read or influence another’s session.

Sources

Technical facts come from these sources. Response priorities and recommended actions are Oktsec’s analysis.

Strands A2A session isolation advisoryStrands Agents · Vendor notice · Checked Oct 25, 2026 UTC
AWS security bulletin 2026-146AWS · Vendor notice · Checked Oct 25, 2026 UTC

Editorial record1 entry

Oct 25, 2026 UTCAdded coverage of the October 22 advisory. Radar publication is not a new disclosure or evidence of a new attack.