CVE-2023-30858Public exploitNetwork attack vector

Service delay via polynomial reTrimSpace matching

Published Apr 28, 2023 · Updated Jan 30, 2025

Regular expression denial of service in Denosaurs emoji before 0.3.0 allows remote attackers to delay responses with large input. The reTrimSpace expression used by replace, unemojify, and strip performs second-degree polynomial matching on crafted whitespace-heavy input instead of using the runtime's linear trim operation. Exposure requires an application to pass remote input to one of those library functions, where excessive CPU work can delay the calling service without affecting confidentiality or integrity.

CVSS severity5.3
Medium
EPSS probability1.16%
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 Denosaurs emoji before 0.3.0 allows remote attackers to delay responses with large input. The reTrimSpace expression used by replace, unemojify, and strip performs second-degree polynomial matching on crafted whitespace-heavy input instead of using the runtime's linear trim operation. Exposure requires an application to pass remote input to one of those library functions, where excessive CPU work can delay the calling service without affecting confidentiality or integrity.

The record

CVE
CVE-2023-30858
Published
Apr 28, 2023
Updated
Jan 30, 2025
Vendor
Denosaurs
Product
emoji
Classifications
CWE-1333, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 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?

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

  1. Affected versionversion=< 0.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Denosaurs · emojiversion=< 0.3.0

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5NIST NVDCVSS: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.

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 exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.004Application or System Exploitation

Public exploit references

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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