CVE-2023-28755Network attack vector

CPU exhaustion via inefficient URL-parsing regexes

Published Mar 31, 2023 · Updated Nov 4, 2025

Regular expression denial of service in affected Ruby URI releases through 0.12.0 allows remote attackers to exhaust CPU via crafted invalid URLs. The URI parser applies inefficient regular-expression processing to invalid URL strings containing specific characters, causing parsing time to grow excessively. Exposure requires an application to pass attacker-controlled URL text to URI parsing; successful exploitation delays or stalls the affected process without disclosed data access or modification.

CVSS severity7.5
High
EPSS probability2.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in affected Ruby URI releases through 0.12.0 allows remote attackers to exhaust CPU via crafted invalid URLs. The URI parser applies inefficient regular-expression processing to invalid URL strings containing specific characters, causing parsing time to grow excessively. Exposure requires an application to pass attacker-controlled URL text to URI parsing; successful exploitation delays or stalls the affected process without disclosed data access or modification.

The record

CVE
CVE-2023-28755
Published
Mar 31, 2023
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1333, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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