CVE-2024-56828

CVE-2024-56828 is a critical-severity vulnerability in 1000mz Chestnutcms with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-434.

Key facts

Description

File Upload vulnerability in ChestnutCMS through 1.5.0. Based on the code analysis, it was determined that the /api/member/avatar API endpoint receives a base64 string as input. This string is then passed to the memberService.uploadAvatarByBase64 method for processing. Within the service, the base64-encoded image is parsed. For example, given a string like: data:image/html;base64,PGh0bWw+PGltZyBzcmM9eCBvbmVycm9yPWFsZXJ0KDEpPjwvaHRtbD4= the content after the comma is extracted and decoded using Base64.getDecoder().decode(). The substring from the 11th character up to the first occurrence of a semicolon (;) is assigned to the suffix variable (representing the file extension). The decoded content is then written to a file. However, the file extension is not validated, and since this functionality is exposed to the frontend, it poses significant security risks.

Frequently asked questions

What is CVE-2024-56828?
File Upload vulnerability in ChestnutCMS through 1.5.0. Based on the code analysis, it was determined that the /api/member/avatar API endpoint receives a base64 string as input. This string is then passed to the memberService.uploadAvatarByBase64 method for processing. Within the service, the base64-encoded image is parsed. For example, given a string like: data:image/html;base64,PGh0bWw+PGltZyBzcmM9eCBvbmVycm9yPWFsZXJ0KDEpPjwvaHRtbD4= the content after the comma is extracted and decoded using Base64.getDecoder().decode(). The substring from the 11th character up to the first occurrence of a semicolon (;) is assigned to the suffix variable (representing the file extension). The decoded content is then written to a file. However, the file extension is not validated, and since this functionality is exposed to the frontend, it poses significant security risks.
How severe is CVE-2024-56828?
CVE-2024-56828 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2024-56828 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-56828?
CVE-2024-56828 affects 1000mz Chestnutcms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-56828?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2024-56828 have an EU (EUVD) identifier?
Yes. CVE-2024-56828 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-53439.
When was CVE-2024-56828 published?
CVE-2024-56828 was published on 2025-01-06 and last updated on 2026-06-17.

References

Affected products (1)

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