How severe is CVE-2026-5323?

No CVSS score has been assigned to CVE-2026-5323 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-5323?

CVE-2026-5323 affects the following packages: a11y-mcp (npm). Ecosystems affected: npm.

How do I fix CVE-2026-5323?

Update a11y-mcp to 1.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-5323 is resolved across your whole dependency graph.

How do I detect CVE-2026-5323 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for a11y-mcp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-5323 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-5323 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-5323 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-5323?

CVE-2026-5323 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 3th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-5323?

CVE-2026-5323 is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-5323 published, and has it been updated?

CVE-2026-5323 was published on April 2, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-5323: a11y-mcp SSRF

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-5323.

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs3th percentile — riskier than 3% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

1other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

a11y-mcpnpm

496downloads / week

Description

A vulnerability was found in priyankark a11y-mcp up to 1.0.5. This vulnerability affects the function A11yServer of the file src/index.js. The manipulation results in server-side request forgery. The attack must be initiated from a local position. The exploit has been made public and could be used. This product operates on a rolling release basis, ensuring continuous delivery. Consequently, there are no version details for either affected or updated releases. Upgrading to version 1.0.6 is able to resolve this issue. The patch is identified as e3e11c9e8482bd06b82fd9fced67be4856f0dffc. It is recommended to upgrade the affected component. The vendor acknowledged the issue but provides additional context for the CVSS rating: "a11y-mcp is a local stdio MCP server - it has no HTTP endpoint and is not network-accessible. The caller is always the local user or an LLM acting on their behalf with user approval."

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`a11y-mcp`	all versions	1.0.5`npm install a11y-mcp@1.0.5`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for a11y-mcp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update a11y-mcp to 1.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-5323 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

A vulnerability was found in priyankark a11y-mcp up to 1.0.5. This vulnerability affects the function A11yServer of the file src/index.js. The manipulation results in server-side request forgery. The attack must be initiated from a local position. The exploit has been made public and could be used. This product operates on a rolling release basis, ensuring continuous delivery. Consequently, there are no version details for either affected or updated releases. Upgrading to version 1.0.6 is able to resolve this issue. The patch is identified as e3e11c9e8482bd06b82fd9fced67be4856f0dffc. It is rec

O3 Security · Impact-Aware SCA

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CVE-2026-5323 — a11y-mcp