CVE-2026-59124Network attack vector

Remote code execution via Web Portal cookie deserialization

Published Aug 11, 2026 · Updated Aug 25, 2026

Deserialization of untrusted data in Microsoft HPC Pack 2019 before 6.3.8359 allows remote attackers to execute code via crafted requests. Microsoft's KB5124659 fix states that the vulnerable Web Portal path deserializes the job-list preferences cookie on the head node, allowing specially crafted input to reach code execution. Exposure is limited to clusters that expose the HPC Web Portal or related head-node services; Microsoft's public records conflict on the gate, with the CVE scored PR:N while the fix note describes authenticated users.

CVSS severity9.8
Critical
EPSS probability1.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization of untrusted data in Microsoft HPC Pack 2019 before 6.3.8359 allows remote attackers to execute code via crafted requests. Microsoft's KB5124659 fix states that the vulnerable Web Portal path deserializes the job-list preferences cookie on the head node, allowing specially crafted input to reach code execution. Exposure is limited to clusters that expose the HPC Web Portal or related head-node services; Microsoft's public records conflict on the gate, with the CVE scored PR:N while the fix note describes authenticated users.

The record

CVE
CVE-2026-59124
Published
Aug 11, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1190
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8Microsoft CorporationCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

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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