CVE-2025-6518: Pyspur Pyspur Incomplete Filtering Of Special Vulnerability

LOW
Advisory Identifier: GHSA-8gff-cf92-72pv
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CVSS 6.3
CWE-791
Published
Advisory Summary

CVE-2025-6518 is a LOW (CVSS 6.3) pyspur incomplete filtering of special vulnerability (CWE-791: Incomplete Filtering of Special Elements) affecting Pyspur libraries in the PyPI ecosystem. The issue involves pyspur incomplete filtering of special elements allowed by singlellmcallnode function. Remediation is available in the latest vendor maintenance releases.

CVE-2025-6518 at a Glance

CVE Identifier CVE-2025-6518
GHSA Identifier GHSA-8gff-cf92-72pv
Severity LOW
CVSS v3.1 Base Score 6.3
CWE Classification CWE-791: Incomplete Filtering of Special Elements
Affected Product Pyspur
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.3

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:N/S:U/C:L/I:L/A:L).

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

How to Fix CVE-2025-6518

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

pyspur fixed: Latest secure release 
pip install pyspur>=Latest secure release
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 pyspur

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-6518, inspect your installed packages using pip:

pip show pyspur

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

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-791: Incomplete Filtering of Special Elements, where the product receives data from an upstream component, but does not completely filter special elements before sending it to a downstream component. In Pyspur, 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

A vulnerability was found in PySpur-Dev pyspur up to 0.1.18. It has been classified as critical. Affected is the function SingleLLMCallNode of the file backend/pyspur/nodes/llm/single_llm_call.py of the component Jinja2 Template Handler. The manipulation of the argument user_message leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

CVE-2025-6518 Affected Pyspur Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
pyspur
pypi/pyspur
PyPI
≤ 0.1.18

References

NVD — CVE-2025-6518 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-6518
Pyspur Source Repository REPOSITORY
https://github.com/PySpur-Dev/pyspur/issues/289
Pyspur Source Repository REPOSITORY
https://github.com/PySpur-Dev/pyspur
vuldb.com/ WEB
https://vuldb.com/?ctiid.313638
vuldb.com/ WEB
https://vuldb.com/?id.313638
vuldb.com/ WEB
https://vuldb.com/?submit.593612

Frequently Asked Questions

What is CVE-2025-6518?
CVE-2025-6518 is a security vulnerability in Pyspur involving pyspur Incomplete Filtering of Special Elements allowed by SingleLLMCallNode function under CWE-791: Incomplete Filtering of Special Elements.
Which Pyspur versions are affected?
Affected versions include releases prior to current release patches across affected packages: pyspur.
What version fixes CVE-2025-6518?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is pyspur affected?
Yes, pyspur is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2025-6518?
CVE-2025-6518 has a CVSS v3.1 base score of 6.3 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2025-6518?
CVE-2025-6518 is classified under CWE-791: Incomplete Filtering of Special Elements (The product receives data from an upstream component, but does not completely filter special elements before sending it to a downstream component.).
How can I check PyPI dependencies for CVE-2025-6518?
Run the dependency tree command: 'pip show pyspur'. 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-8gff-cf92-72pv",
  "modified" : "2025-06-25T14:12:09Z",
  "published" : "2025-06-23T21:31:56Z",
  "aliases" : [ "CVE-2025-6518" ],
  "summary" : "pyspur Incomplete Filtering of Special Elements allowed by SingleLLMCallNode function",
  "details" : "A vulnerability was found in PySpur-Dev pyspur up to 0.1.18. It has been classified as critical. Affected is the function SingleLLMCallNode of the file backend/pyspur/nodes/llm/single_llm_call.py of the component Jinja2 Template Handler. The manipulation of the argument user_message leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyspur"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.1.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-6518"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/PySpur-Dev/pyspur/issues/289"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/PySpur-Dev/pyspur"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/?ctiid.313638"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/?id.313638"
  }, {
    "type" : "WEB",
    "url" : "https://vuldb.com/?submit.593612"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-791" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-06-25T14:12:09Z",
    "nvd_published_at" : "2025-06-23T19:15:25Z"
  }
}