November 14, 2026

CVE Watchtower

CVE-2026-123364OctoPrint >= 2.0.0rc1, Cross-site Scripting (XSS)

NVD

Vulnerability Summary

## Impact

OctoPrint versions 2.0.0rc1 up until version 2.0.0rc6 are susceptible to cross-site scripting via a specially crafted default `port` or `baudrate` setting on the bundled Serial Connector plugin, supplied via the API as new defaults during a `connect` request.

## Patches

The vulnerability is patched in 2.0.0rc7.

## Workaround

Check `config.yaml` for Javascript fragments in `printerConnection.preferred.parameters.port` or `printerConnection.preferred.parameters.baudrate`. If found, remove them. You can check who of your users had access to your instance since you flashed 2.0.0rc1 or above via `auth.log`.

## Credits

This vulnerability was discovered and responsibly disclosed to OctoPrint by "mahn-don".

## Timeline

2026-10-14: Report received
2026-10-14: Report acknowledged
2026-10-14: Report verified
2026-10-14: Fix ready for 2.0.0rc7
2026-10-20: CVE requested
Severity Level
LOW
Published Date
Nov 9, 2026
Last Modified
Nov 10, 2026
Exploitation Status
No confirmed exploitation yet
CVE Record Status
Published
EPSS Score (30-Day)
0.25%Probability
Root Weakness (CWE)
CWE-79: Cross-site Scripting (XSS) β†—
The software does not neutralize user-controllable input before it is placed in output that is used as a web page.
CVSS v4.0 Base Metrics — Score 2.4
CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N
Attack VectorAdjacent
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredLow
User InteractionPassive
Confidentiality (Vulnerable System)Low
Integrity (Vulnerable System)Low
Availability (Vulnerable System)Low
Confidentiality (Subsequent System)Low
Integrity (Subsequent System)Low
Availability (Subsequent System)None

Affected & Patched Versions

Affected Versions
  • OctoPrint >= 2.0.0rc1, <= 2.0.0rc6
Patched Versions
No patched version published yet
Until a fix ships, reduce exposure:
  • Restrict access to the affected service or interface to trusted networks.
  • Disable the affected feature if you do not need it.
  • Watch the vendor advisory for a firmware or software update.

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run OctoPrint >= 2.0.0rc1, and which version.
  2. No patched version is listed yet. Limit access to the affected service to trusted networks, and disable the feature if you can.
  3. Subscribe to the vendor advisory so you learn when a fix ships.

Timeline

  • Nov 9, 2026Published
  • Nov 10, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 10, 2026 17:00 UTC