CVE-2026-31239Network attack vector

Arbitrary code execution via unsafe model deserialization

Published May 12, 2026 · Updated May 12, 2026

Insecure deserialization in mamba-ssm 2.2.6 and earlier allows attackers to execute arbitrary code through a malicious Hugging Face model. MambaLMHeadModel.from_pretrained() passes pytorch_model.bin to torch.load() without weights_only=True, allowing pickle to instantiate attacker-controlled Python objects. Exploitation requires the process to load weights from an attacker-published model repository, and the resulting code runs with the mamba process's privileges.

CVSS severity9.8
Critical
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure deserialization in mamba-ssm 2.2.6 and earlier allows attackers to execute arbitrary code through a malicious Hugging Face model. MambaLMHeadModel.from_pretrained() passes pytorch_model.bin to torch.load() without weights_only=True, allowing pickle to instantiate attacker-controlled Python objects. Exploitation requires the process to load weights from an attacker-published model repository, and the resulting code runs with the mamba process's privileges.

The record

CVE
CVE-2026-31239
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, CAPEC-586, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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