CVE-2026-5140

High

Published: 29 April 2026

Published

29 April 2026

Modified

04 May 2026

KEV Added

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Patch

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CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Score 0.0006 18.3th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-5140 is a high-severity CRLF Injection (CWE-93) vulnerability in Gov (inferred from references). Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 18.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

SI-10 directly requires validation and neutralization of malicious inputs like CRLF sequences to prevent injection attacks that bypass authentication in Pardus Update.

SI-2 Flaw Remediation good match

prevent

SI-2 ensures timely remediation of the specific CRLF injection flaw by patching Pardus Update to version 0.8.0 or later.

SI-15 Information Output Filtering partial match

prevent

SI-15 filters outputs to block CRLF sequences from manipulating responses and enabling authentication bypass.

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 →

Why these techniques?

The CRLF injection vulnerability enables remote unauthenticated attackers to bypass authentication in network-accessible Pardus software, directly facilitating initial access through exploitation of a public-facing application.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Improper neutralization of CRLF sequences ('CRLF injection') vulnerability in TUBITAK BILGEM Software Technologies Research Institute Pardus Update allows Authentication Bypass. This issue affects Pardus Update: from 0.6.3 before 0.6.4.

Deeper analysisAI

CVE-2026-5140 is an improper neutralization of CRLF sequences, known as a CRLF injection vulnerability, in Pardus software developed by TUBITAK BILGEM Software Technologies Research Institute. This flaw enables authentication bypass and affects Pardus versions from <=0.6.4 before 0.8.0. The vulnerability is classified under CWE-93 and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant confidentiality, integrity, and availability impacts.

A remote, unauthenticated attacker can exploit this vulnerability over the network with low complexity, though it requires user interaction to succeed. By injecting CRLF sequences, the attacker can bypass authentication mechanisms, potentially gaining unauthorized access to the affected system. Successful exploitation could lead to high-impact outcomes, including data exposure, modification of system resources, and disruption of services.

The advisory from USOM (https://www.usom.gov.tr/bildirim/tr-26-0131) provides details on this vulnerability, including recommended mitigations such as upgrading to Pardus version 0.8.0 or later. Security practitioners should consult this reference for patch information and additional guidance.