Cyber Resilience

CVE-2026-2878

Progress Telerik Ui For Asp.Net Ajax ≤ 2026.1.225

Published
25 February 2026
Modified
26 February 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS Score 0.0018 7th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-2878 is a medium-severity Insufficient Entropy (CWE-331) vulnerability in Progress Telerik Ui For Asp.Net Ajax. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-5 (Authenticator Management) and SC-13 (Cryptographic Protection) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

In Progress® Telerik® UI for AJAX, versions prior to 2026.1.225, an insufficient entropy vulnerability exists in RadAsyncUpload, where a predictable temporary identifier, based on timestamp and filename, can enable collisions and file content tampering.

CWE(s)
CWE-331

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1565.001 Stored Data Manipulation Impact
Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
Why these techniques?

Vuln in public-facing Telerik AJAX upload component enables direct exploitation (T1190) and stored file tampering via predictable IDs (T1565.001).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-6023Same product: Progress Telerik Ui For Asp.Net Ajax
CVE-2017-11357Same product: Progress Telerik Ui For Asp.Net Ajax
CVE-2025-3600Same product: Progress Telerik Ui For Asp.Net Ajax
CVE-2026-6022Same product: Progress Telerik Ui For Asp.Net Ajax
CVE-2026-8037Same vendor: Progress
CVE-2026-10698Same vendor: Progress
CVE-2025-13774Same vendor: Progress
CVE-2026-8649Same vendor: Progress
CVE-2026-8651Same vendor: Progress
CVE-2026-2699Same vendor: Progress

Affected Assets

progress
telerik ui for asp.net ajax
≤ 2026.1.225

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • IA-5 Authenticator Management
  • SC-13 Cryptographic Protection
Detect
Catch it (NIST detect / respond)
  • SI-7 Software, Firmware, and Information Integrity
Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.5.2
  • V11.3.4

Mitigating Controls (NIST 800-53 r5) AI

IA-5 Authenticator Management good match
prevent

Requires management of identifiers and authenticators with sufficient entropy, directly preventing predictable timestamp/filename-based temporary IDs in RadAsyncUpload.

SC-13 Cryptographic Protection good match
prevent

Mandates cryptographic protection mechanisms that enforce cryptographically strong random number generation for identifiers, eliminating the CWE-331 weakness.

SI-7 Software, Firmware, and Information Integrity partial match
detect

Detects unauthorized modification of uploaded file content resulting from ID collisions or tampering attempts.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices explicitly include vetted RNG and entropy sources, directly preventing this weakness while covering many other development concerns.

PR.AA-03 partial match
prevents

Password-strength policies implicitly require sufficient entropy, but the control addresses authentication rather than algorithmic randomness.

PR.DS-01 partial match
prevents

Proper encryption for data-at-rest requires sufficient entropy for keys/nonces; eliminating the weakness therefore supports but does not fully realize the control.

PR.DS-02 partial match
prevents

Cryptographic protection of data-in-transit depends on adequate entropy; the weakness directly undermines the control's effectiveness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography mostly match
prevents

Mandates use of cryptography that must rely on sufficient entropy sources.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can detect insufficient-entropy defects before release.

A.8.25 Secure development life cycle partial match
prevents

Secure-SDLC activities include entropy validation during design and testing.

A.8.28 Secure coding partial match
prevents

Secure-coding rules can explicitly forbid weak random-number generation.

A.8.5 Secure authentication partial match
degrades

Requires secure authentication mechanisms that depend on unpredictable secrets.

Hardening callouts derived

Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).

Oracle Linux 8 (1 rule)
  • V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. via CWE-331
RHEL 8 (1 rule)
  • V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. via CWE-331

References