CVE-2026-107396: Indico Cross-Site-Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-c4wc-ggrj-jg9v
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CVSS 5.4
CWE-692
Published
Advisory Summary

CVE-2026-107396 is a MODERATE (CVSS 5.4) cross-site-scripting vulnerability (CWE-692: Incomplete Denylist to Cross-Site Scripting) affecting Indico libraries in the PyPI ecosystem. The issue involves cross-site-scripting in link fields. Remediation is available by upgrading affected packages to version 3.3.13.

CVE-2026-107396 at a Glance

CVE Identifier CVE-2026-107396
GHSA Identifier GHSA-c4wc-ggrj-jg9v
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-692: Incomplete Denylist to Cross-Site Scripting
Affected Product Indico
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-107396

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

indico fixed: 3.3.13 
pip install indico>=3.3.13
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 indico

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-107396, inspect your installed packages using pip:

pip show indico

Analyze the terminal output to locate any version of Indico in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.3.13), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-692: Incomplete Denylist to Cross-Site Scripting, where the product uses a denylist-based protection mechanism to defend against xss attacks, but the denylist is incomplete, allowing xss variants to succeed. In Indico, 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 There is a Cross-Site-Scripting vulnerability in fields that allow entering custom URLs. ### Patches You should to update to [Indico 3.3.13](https://github.com/indico/indico/releases/tag/v3.3.13) as soon as possible. See [the docs](https://docs.getindico.io/en/stable/installation/upgrade/) for instructions on how to update. ### Workarounds - Set `CSP_ENABLED = True` in `indico.conf` - **this is recommended regardless of updating**. - Only let trustworthy users manage events or create content (including material uploads which speakers can typically do as well) on Indico. ### For more information If you have any questions or comments about this advisory: - Open a thread in [our forum](https://talk.getindico.io/) - Email us privately at [indico-team@cern.ch](mailto:indico-team@cern.ch)

CVE-2026-107396 Affected Indico Versions

1 component(s)
Fixed Versions:
3.3.13
Product / Package Ecosystem Affected Versions Fixed Version
indico
pypi/indico
PyPI
< 3.3.13
3.3.13

References

GitHub Advisory / Wiki ADVISORY
https://github.com/indico/indico/security/advisories/GHSA-c4wc-ggrj-jg9v
NVD — CVE-2026-107396 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-107396
Indico Source Repository REPOSITORY
https://github.com/indico/indico/pull/7619
Security Fix Commit FIX COMMIT
https://github.com/indico/indico/commit/d4c8c7127176efa4cb53c64119ca8ee2b551be18
Indico Source Repository REPOSITORY
https://github.com/indico/indico
Indico Release RELEASE
https://github.com/indico/indico/releases/tag/v3.3.13

Frequently Asked Questions

What is CVE-2026-107396?
CVE-2026-107396 is a security vulnerability in Indico involving Cross-Site-Scripting in link fields under CWE-692: Incomplete Denylist to Cross-Site Scripting.
Which Indico versions are affected?
Affected versions include releases prior to 3.3.13 across affected packages: indico.
What version fixes CVE-2026-107396?
Upgrading to 3.3.13 (or the latest patched release for your respective branch) resolves the vulnerability.
Is indico affected?
Yes, indico is affected in releases prior to 3.3.13. Upgrade your dependency to 3.3.13 or later.
What is the CVSS score of CVE-2026-107396?
CVE-2026-107396 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-107396?
CVE-2026-107396 is classified under CWE-692: Incomplete Denylist to Cross-Site Scripting (The product uses a denylist-based protection mechanism to defend against XSS attacks, but the denylist is incomplete, allowing XSS variants to succeed.).
How can I check PyPI dependencies for CVE-2026-107396?
Run the dependency tree command: 'pip show indico'. 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-c4wc-ggrj-jg9v",
  "modified" : "2026-10-08T22:09:41Z",
  "published" : "2026-10-08T22:09:41Z",
  "aliases" : [ "CVE-2026-107396" ],
  "summary" : "Indico: Cross-Site-Scripting in link fields",
  "details" : "### Impact\nThere is a Cross-Site-Scripting vulnerability in fields that allow entering custom URLs.\n\n### Patches\nYou should to update to [Indico 3.3.13](https://github.com/indico/indico/releases/tag/v3.3.13) as soon as possible.\nSee [the docs](https://docs.getindico.io/en/stable/installation/upgrade/) for instructions on how to update.\n\n### Workarounds\n- Set `CSP_ENABLED = True` in `indico.conf` - **this is recommended regardless of updating**.\n- Only let trustworthy users manage events or create content (including material uploads which speakers can typically do as well) on Indico.\n\n### For more information\nIf you have any questions or comments about this advisory:\n\n- Open a thread in [our forum](https://talk.getindico.io/)\n- Email us privately at [indico-team@cern.ch](mailto:indico-team@cern.ch)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "indico"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.3.13"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/indico/indico/security/advisories/GHSA-c4wc-ggrj-jg9v"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-107396"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/indico/indico/pull/7619"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/indico/indico/commit/d4c8c7127176efa4cb53c64119ca8ee2b551be18"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/indico/indico"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/indico/indico/releases/tag/v3.3.13"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-692" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-08T22:09:41Z",
    "nvd_published_at" : "2026-10-08T20:17:34Z"
  }
}