CVE-2021-26589Network attack vector

Session-cookie exposure via missing HttpOnly attribute

Published Oct 19, 2021 · Updated Aug 3, 2024

Cross-site scripting in HPE Superdome Flex Server firmware before 3.40.106 allows remote attackers to access session cookies. The Rack Management Controller issues its session cookie without the HttpOnly attribute, allowing browser-executed script to read the cookie; HPE has not published the cookie name or affected request path. Exploitation requires user interaction and script execution in the management interface, and the documented impact is limited to session-cookie exposure and cross-site scripting effects.

CVSS severity6.1
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in HPE Superdome Flex Server firmware before 3.40.106 allows remote attackers to access session cookies. The Rack Management Controller issues its session cookie without the HttpOnly attribute, allowing browser-executed script to read the cookie; HPE has not published the cookie name or affected request path. Exploitation requires user interaction and script execution in the management interface, and the documented impact is limited to session-cookie exposure and cross-site scripting effects.

The record

CVE
CVE-2021-26589
Published
Oct 19, 2021
Updated
Aug 3, 2024
Vendor
Hewlett Packard Enterprise (HPE)
Product
HPE Superdome Flex Server
Classifications
CWE-732, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Prior to Version 3.40.106

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Hewlett Packard Enterprise (HPE) · HPE Superdome Flex Serverversion=Prior to Version 3.40.106

Published CVSS scores

6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:N/I:P/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-732Incorrect Permission Assignment for Critical Resource
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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