Cyber Resilience

CVE-2023-28756

Fedoraproject Fedora 36 … 38

Published
31 March 2023
Modified
04 November 2025
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:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.025 83th percentile
Risk Priority 49 floored blend · peak EPSS

Summary

CVE-2023-28756 is a medium-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Fedoraproject Fedora. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 17% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

A ReDoS issue was discovered in the Time component through 0.2.1 in Ruby through 3.2.1. The Time parser mishandles invalid URLs that have specific characters. It causes an increase in execution time for parsing strings to Time objects. The fixed…

more

versions are 0.1.1 and 0.2.2.

CWE(s)
CWE-1333

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-28755Same product: Debian Debian Linux
CVE-2023-36053Same product: Debian Debian Linux
CVE-2025-27220Same product: Ruby-Lang Ruby
CVE-2023-26117Same product: Fedoraproject Fedora
CVE-2023-26118Same product: Fedoraproject Fedora
CVE-2024-25126Same product: Debian Debian Linux
CVE-2024-3772Same product: Fedoraproject Fedora
CVE-2023-30608Same product: Debian Debian Linux
CVE-2024-26146Same product: Debian Debian Linux
CVE-2023-26116Same product: Fedoraproject Fedora

Affected Assets

ruby-lang
ruby
≤ 2.7.7
ruby-lang
time
0.1.0, 0.2.1
debian
debian linux
10.0
fedoraproject
fedora
36, 37, 38

Mitigating Controls

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 directly prevent inefficient regex via reviews, static analysis, and safe libraries.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover ReDoS issues in existing code but do not stop their introduction.

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect and reject regex patterns with exponential worst-case complexity.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates review of algorithmic efficiency, directly addressing ReDoS-prone regex.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input-validation rules that limit regex complexity.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage avoidance of computationally expensive constructs such as catastrophic backtracking.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly prohibit or limit the use of inefficient regular expressions.

References