HeliumEdu Helium up to 2.2.59 Attachment Serializer attachmentserializer.py unrestricted upload

Summaryinfo

A vulnerability was found in HeliumEdu Helium up to 2.2.59 and classified as critical. The impacted element is an unknown function of the file helium/planner/serializers/attachmentserializer.py of the component Attachment Serializer. Such manipulation leads to unrestricted upload. This vulnerability is documented as CVE-2026-55876. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in HeliumEdu Helium up to 2.2.59 and classified as critical. Affected by this issue is an unknown code of the file helium/planner/serializers/attachmentserializer.py of the component Attachment Serializer. The manipulation with an unknown input leads to a unrestricted upload vulnerability. Using CWE to declare the problem leads to CWE-434. The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Helium is a free online student planner for classes, homework, grades, and notes. Prior to 2.2.60, the POST /planner/attachments/ endpoint allows authenticated users to upload SVG and HTML attachments because conf/configs/common.py omits those formats from BLOCKED_ATTACHMENT_EXTENSIONS and BLOCKED_ATTACHMENT_MIME_TYPES, and helium/planner/serializers/attachmentserializer.py relies on those blocklists. An uploaded SVG served as image/svg+xml can execute embedded script when a visitor opens its public attachment URL, allowing persistent attacker-controlled active content and phishing under an application-managed storage URL. The attachment storage uses a separate origin from the application, so same-origin policy prevents the script from reading application cookies or storage, and application-session compromise is not supported by the maintained deployment configuration. This issue is fixed in version 2.2.60.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-55876 since 06/17/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1608.002 by the MITRE ATT&CK project.

Upgrading to version 2.2.60 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• HeliumEdu

Name

• Helium

Version

• 2.2.0
• 2.2.1
• 2.2.2
• 2.2.3
• 2.2.4
• 2.2.5
• 2.2.6
• 2.2.7
• 2.2.8
• 2.2.9
• 2.2.10
• 2.2.11
• 2.2.12
• 2.2.13
• 2.2.14
• 2.2.15
• 2.2.16
• 2.2.17
• 2.2.18
• 2.2.19
• 2.2.20
• 2.2.21
• 2.2.22
• 2.2.23
• 2.2.24
• 2.2.25
• 2.2.26
• 2.2.27
• 2.2.28
• 2.2.29
• 2.2.30
• 2.2.31
• 2.2.32
• 2.2.33
• 2.2.34
• 2.2.35
• 2.2.36
• 2.2.37
• 2.2.38
• 2.2.39
• 2.2.40
• 2.2.41
• 2.2.42
• 2.2.43
• 2.2.44
• 2.2.45
• 2.2.46
• 2.2.47
• 2.2.48
• 2.2.49
• 2.2.50
• 2.2.51
• 2.2.52
• 2.2.53
• 2.2.54
• 2.2.55
• 2.2.56
• 2.2.57
• 2.2.58
• 2.2.59

CPE 2.3info

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CPE 2.2info

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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