CVE-2026-2878Network attack vector

File tampering via predictable temporary upload identifiers

Published Feb 25, 2026 · Updated Feb 25, 2026

Insufficient entropy in RadAsyncUpload before 2026.1.225 allows remote attackers to tamper with uploaded file content via identifier collisions. RadAsyncUpload constructs a temporary UploadID from the upload timestamp and filename, making the victim's full temporary-file path predictable. Exploitation requires an unauthenticated network attacker to win a timing-dependent collision during another user's upload, allowing file content replacement without disclosure or service interruption.

CVSS severity5.3
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in RadAsyncUpload before 2026.1.225 allows remote attackers to tamper with uploaded file content via identifier collisions. RadAsyncUpload constructs a temporary UploadID from the upload timestamp and filename, making the victim's full temporary-file path predictable. Exploitation requires an unauthenticated network attacker to win a timing-dependent collision during another user's upload, allowing file content replacement without disclosure or service interruption.

The record

CVE
CVE-2026-2878
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
Progress Software Corporation
Product
Telerik UI for ASP.NET AJAX
Classifications
CWE-331, CAPEC-26, CAPEC-149, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 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?

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

  1. Affected versionversion=2011.2.712 <2026.1.225

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Progress Software Corporation · Telerik UI for ASP.NET AJAXversion=2011.2.712 <2026.1.225

Published CVSS scores

5.3Progress Software CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
5.9NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy
CAPEC-26Leveraging Race Conditions
CAPEC-149Explore for Predictable Temporary File Names
T1565.001Stored Data Manipulation

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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