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CVE-2026-77811 - Stored Cross-Site Scripting via Integration Template Asset in OpenSearch Dashboards

unknownCVE-2026-77811
Bulletin ID: 2026-088-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 08/21/2026 13:00 PM PDT Description: Amazon OpenSearch Service is a managed service that makes it easy to deploy, operate, and scale OpenSearch clusters. We identified CVE-2026-77811, a stored cross-site scripting issue in the dashboards-observability plugin in OpenSearch Dashboards. Improper input validation in the integrations static file endpoint allows a remote authenticated actor with write permissions to OpenSearch Dashboards saved objects to upload a custom integration containing arbitrary JavaScript. When another user accesses the static file endpoint directly, the script executes in their browser session and can perform actions on their behalf, including making API calls to OpenSearch with their privileges. Affected products & versions: OpenSearch Dashboards dashboards-observability plugin (open-source, self-managed): - Affected: versions before 3.4 and versions before 2.19.6 - Fixed: versions 3.4 and 2.19.6 Amazon OpenSearch Service (AWS Managed): - Affected: versions before 3.3 - Fixed: fixed in all affected versions (via service software update) Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.

CSIRTS triage

vendor: AWSproduct: OpenSearch DashboardsCross-site scripting
What
Stored cross-site scripting in the dashboards-observability plugin's integrations static file endpoint due to improper input validation.
Who is affected
Authenticated users with write permissions to OpenSearch Dashboards saved objects can inject malicious scripts affecting other users.
Urgency
Important — requires authenticated attacker with write access; can perform actions with victim's privileges.
Action
Upgrade OpenSearch Dashboards to patched version when available.

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Details

Source
AWS Security Bulletins (INTL · vendor-psirt · site)
Severity
unknown
Published
2026-08-21
Exploitation
Not in CISA KEV at last sync

Original advisory: https://aws.amazon.com/security/security-bulletins/rss/2026-088-aws/

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-77811coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for - Stored Cross-Site

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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