CVE-2026-35163: OctoPrint Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-p6qx-ghxm-389h
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CWE-80
Published
Advisory Summary

CVE-2026-35163 is a MODERATE cross-site scripting vulnerability (CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)) affecting OctoPrint libraries in the PyPI ecosystem. The issue involves octoprint has xss in its suppressed command notifications. Remediation is available by upgrading affected packages to version 1.11.8, 2.0.0rc3.

CVE-2026-35163 at a Glance

CVE Identifier CVE-2026-35163
GHSA Identifier GHSA-p6qx-ghxm-389h
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Affected Product OctoPrint
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-35163

To remediate this vulnerability, upgrade all affected OctoPrint dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

OctoPrint fixed: 1.11.8 
pip install OctoPrint>=1.11.8
OctoPrint fixed: 2.0.0rc3 
pip install OctoPrint>=2.0.0rc3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show OctoPrint

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-35163, inspect your installed packages using pip:

pip show OctoPrint

Analyze the terminal output to locate any version of OctoPrint in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.11.8), your application is affected.

Note: The pip show OctoPrint command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS), where the product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. In OctoPrint, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact OctoPrint versions up to and including 1.11.7 as well as 2.0.0rc1 and 2.0.0rc2 are affected by a vulnerability that allows injection of arbitrary HTML and JavaScript into Suppressed Command notifications popups generated by the printer. An attacker who successfully convinces a victim to print a specially crafted file could exploit this issue to disrupt ongoing prints, extract information (including sensitive configuration settings, if the targeted user has the necessary permissions for that), or perform other actions on behalf of the targeted user within the OctoPrint instance. ### Patches The vulnerability has been patched in version 1.11.8 and 2.0.0rc3. ### Workaround OctoPrint administrators can mitigate the risk by disabling popups: - for Action Command notifications, set _OctoPrint Settings -> Serial Connection -> Behaviour -> Sanity Checking -> Display notifications for suppressed commands_ to _Never show notifications_ It is also strongly recommended to ensure that files being printed originate from trusted sources, and, whenever possible, are sliced with an application's own slicer. ### Credits This vulnerability was discovered and responsibly disclosed to OctoPrint by [Jacopo Tediosi](https://github.com/jacopotediosi). ### Timeline 2026-03-18: Report received 2026-04-01: Report verified 2026-04-01: Fix ready for 2.0.0 2026-06-22: Fix backported to 1.11.x 2026-06-23: Fix released with 1.11.8 and 2.0.0rc3

CVE-2026-35163 Affected OctoPrint Versions

2 component(s)
Fixed Versions:
1.11.82.0.0rc3
Product / Package Ecosystem Affected Versions Fixed Version
OctoPrint
pypi/OctoPrint
PyPI
< 1.11.8
1.11.8
OctoPrint
pypi/OctoPrint
PyPI
≥ 2.0.0rc1
< 2.0.0rc3
2.0.0rc3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/OctoPrint/OctoPrint/security/advisories/GHSA-p6qx-ghxm-389h
NVD — CVE-2026-35163 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35163
OctoPrint Source Repository REPOSITORY
https://github.com/OctoPrint/OctoPrint
OctoPrint Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/octoprint/PYSEC-2026-2688.yaml

Frequently Asked Questions

What is CVE-2026-35163?
CVE-2026-35163 is a security vulnerability in OctoPrint involving OctoPrint has XSS in its Suppressed Command Notifications under CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS).
Which OctoPrint versions are affected?
Affected versions include releases prior to 1.11.8, 2.0.0rc3 across affected packages: OctoPrint.
What version fixes CVE-2026-35163?
Upgrading to 1.11.8, 2.0.0rc3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is OctoPrint affected?
Yes, OctoPrint is affected in releases prior to 1.11.8, 2.0.0rc3. Upgrade your dependency to 1.11.8, 2.0.0rc3 or later.
What CWE is associated with CVE-2026-35163?
CVE-2026-35163 is classified under CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) (The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.).
How can I check PyPI dependencies for CVE-2026-35163?
Run the dependency tree command: 'pip show OctoPrint'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p6qx-ghxm-389h",
  "modified" : "2026-08-21T18:26:50Z",
  "published" : "2026-06-23T17:15:14Z",
  "aliases" : [ "CVE-2026-35163" ],
  "summary" : "OctoPrint has XSS in its Suppressed Command Notifications",
  "details" : "### Impact\n\nOctoPrint versions up to and including 1.11.7 as well as 2.0.0rc1 and 2.0.0rc2 are affected by a vulnerability that allows injection of arbitrary HTML and JavaScript into Suppressed Command notifications popups generated by the printer.\n\nAn attacker who successfully convinces a victim to print a specially crafted file could exploit this issue to disrupt ongoing prints, extract information (including sensitive configuration settings, if the targeted user has the necessary permissions for that), or perform other actions on behalf of the targeted user within the OctoPrint instance.\n\n### Patches\n\nThe vulnerability has been patched in version 1.11.8 and 2.0.0rc3.\n\n### Workaround\n\nOctoPrint administrators can mitigate the risk by disabling popups:\n- for Action Command notifications, set _OctoPrint Settings -> Serial Connection -> Behaviour -> Sanity Checking -> Display notifications for suppressed commands_ to _Never show notifications_\n\nIt is also strongly recommended to ensure that files being printed originate from trusted sources, and, whenever possible, are sliced with an application's own slicer.\n\n### Credits\n\nThis vulnerability was discovered and responsibly disclosed to OctoPrint by [Jacopo Tediosi](https://github.com/jacopotediosi).\n\n### Timeline\n\n2026-03-18: Report received\n2026-04-01: Report verified\n2026-04-01: Fix ready for 2.0.0\n2026-06-22: Fix backported to 1.11.x\n2026-06-23: Fix released with 1.11.8 and 2.0.0rc3",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "OctoPrint"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.11.8"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.11.7"
    }
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "OctoPrint"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0rc1"
      }, {
        "fixed" : "2.0.0rc3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.0.0rc2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/OctoPrint/OctoPrint/security/advisories/GHSA-p6qx-ghxm-389h"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35163"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/OctoPrint/OctoPrint"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/octoprint/PYSEC-2026-2688.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-80" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-23T17:15:14Z",
    "nvd_published_at" : null
  }
}