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High, CVSS 8.3amended

Serena: Unauthenticated Flask dashboard on fixed port enables DNS rebinding → memory poisoning → RCE

CVE-2026-49471GHSA-37h2-6p4f-mp3q

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (serena-agent 1.5.2), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS
  • CVE-2026-49471: 0.37% estimated exploitation activity in the next 30 days; percentile 31.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary Serena's built-in web dashboard exposes an unauthenticated Flask API on a fixed, predictable port (TCP 24282, hardcoded as 0x5EDA in constants.py). The server has no authentication, no CSRF protection, and no Host header validation. A DNS rebinding attack allows a malicious webpage to reach this API from any browser and write arbitrary content to the agent's persistent memory store — which the agent reads and acts on autonomously. Combined with executeshellcommand (enabled by default in all contexts via shell=True), this creates a full remote code execution chain requiring only that the victim visit a malicious webpage while Serena is running. Details Root cause 1 — Unauthenticated dashboard (src/serena/dashboard.py) The Flask server starts automatically (webdashboard: true by default) on a fixed, predictable port with no auth middleware: Flask does not validate the Host header by default (no SERVERNAME set), which is the prerequisite for DNS rebinding. Root cause 2 —…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-37h2-6p4f-mp3q

  2. Revision 1 · created ·

    Published from osv record GHSA-37h2-6p4f-mp3q

Agent brief

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# Patch Next advisory brief: CVE-2026-49471

Advisory: Serena: Unauthenticated Flask dashboard on fixed port enables DNS rebinding → memory poisoning → RCE
IDs: CVE-2026-49471, GHSA-37h2-6p4f-mp3q
Record: https://patchnext.com/advisories/cve-2026-49471 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: serena-agent 1.5.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI serena-agent: affected < 1.5.2; fixed in 1.5.2

## Suggested inspection (read-only)
- `python -m pip show serena-agent`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on serena-agent.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-37h2-6p4f-mp3q (OSV record GHSA-37h2-6p4f-mp3q lists affected ranges: PyPI serena-agent >=0 <1.5.2 (fixed))
- Verified: https://github.com/advisories/GHSA-37h2-6p4f-mp3q (GitHub-reviewed advisory GHSA-37h2-6p4f-mp3q lists affected ranges: PyPI serena-agent >=0 <1.5.2)

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