CVE-2026-31239: Mamba ssm Mamba Language Model Framework Vulnerable Vulnerability

CRITICAL
Advisory Identifier: GHSA-pq2f-x424-6fjm
Share
CVSS 9.8
CWE-502
Published
Advisory Summary

CVE-2026-31239 is a CRITICAL (CVSS 9.8) mamba language model framework vulnerable vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Mamba ssm libraries in the PyPI ecosystem. The issue involves mamba language model framework vulnerable to insecure deserialization when loading pre-trained models from huggingface hub. Remediation is available in the latest vendor maintenance releases.

CVE-2026-31239 at a Glance

CVE Identifier CVE-2026-31239
GHSA Identifier GHSA-pq2f-x424-6fjm
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Mamba ssm
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2026-31239

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

mamba-ssm fixed: Latest secure release 
pip install mamba-ssm>=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 mamba-ssm

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-31239, inspect your installed packages using pip:

pip show mamba-ssm

Analyze the terminal output to locate any version of Mamba ssm 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 mamba-ssm command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Mamba ssm, 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

The mamba language model framework thru 2.2.6 is vulnerable to insecure deserialization (CWE-502) when loading pre-trained models from HuggingFace Hub. The MambaLMHeadModel.from_pretrained() method uses torch.load() to load the pytorch_model.bin weight file without enabling the security-restrictive weights_only=True parameter. This allows the deserialization of arbitrary Python objects via the pickle module. An attacker can exploit this by publishing a malicious model repository on HuggingFace Hub. When a victim loads a model from this repository, arbitrary code is executed on the victim's system in the context of the mamba process.

CVE-2026-31239 Affected Mamba ssm Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
mamba-ssm
pypi/mamba-ssm
PyPI
≤ 2.2.6

References

NVD — CVE-2026-31239 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31239
Mamba ssm Source Repository REPOSITORY
https://github.com/state-spaces/mamba
www.notion.so/cve-2026-31239-35d1... WEB
https://www.notion.so/CVE-2026-31239-35d1e1393188810d9baedfbd8363f396

Frequently Asked Questions

What is CVE-2026-31239?
CVE-2026-31239 is a security vulnerability in Mamba ssm involving mamba language model framework vulnerable to insecure deserialization when loading pre-trained models from HuggingFace Hub under CWE-502: Deserialization of Untrusted Data.
Which Mamba ssm versions are affected?
Affected versions include releases prior to current release patches across affected packages: mamba-ssm.
What version fixes CVE-2026-31239?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is mamba-ssm affected?
Yes, mamba-ssm 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-2026-31239?
CVE-2026-31239 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-31239?
CVE-2026-31239 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check PyPI dependencies for CVE-2026-31239?
Run the dependency tree command: 'pip show mamba-ssm'. 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-pq2f-x424-6fjm",
  "modified" : "2026-05-27T22:09:56Z",
  "published" : "2026-05-12T18:30:41Z",
  "aliases" : [ "CVE-2026-31239" ],
  "summary" : "mamba language model framework vulnerable to insecure deserialization when loading pre-trained models from HuggingFace Hub",
  "details" : "The mamba language model framework thru 2.2.6 is vulnerable to insecure deserialization (CWE-502) when loading pre-trained models from HuggingFace Hub. The MambaLMHeadModel.from_pretrained() method uses torch.load() to load the pytorch_model.bin weight file without enabling the security-restrictive weights_only=True parameter. This allows the deserialization of arbitrary Python objects via the pickle module. An attacker can exploit this by publishing a malicious model repository on HuggingFace Hub. When a victim loads a model from this repository, arbitrary code is executed on the victim's system in the context of the mamba process.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mamba-ssm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.2.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31239"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/state-spaces/mamba"
  }, {
    "type" : "WEB",
    "url" : "https://www.notion.so/CVE-2026-31239-35d1e1393188810d9baedfbd8363f396"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-27T22:09:56Z",
    "nvd_published_at" : "2026-05-12T18:16:52Z"
  }
}