CVE-2023-26364Public exploitNetwork attack vector

CSS parsing denial of service via @import regex

Published Nov 17, 2023 · Updated Aug 29, 2024

Improper input validation in @adobe/css-tools 4.3.0 and earlier allows remote attackers to interrupt CSS parsing with crafted CSS. The parse routine's @import expression backtracks inefficiently over repeated quote-and-colon sequences, consuming excessive CPU while processing the directive. No privileges or user interaction are required, but exposure depends on an application passing attacker-controlled CSS to the library.

CVSS severity5.3
Medium
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in @adobe/css-tools 4.3.0 and earlier allows remote attackers to interrupt CSS parsing with crafted CSS. The parse routine's @import expression backtracks inefficiently over repeated quote-and-colon sequences, consuming excessive CPU while processing the directive. No privileges or user interaction are required, but exposure depends on an application passing attacker-controlled CSS to the library.

The record

CVE
CVE-2023-26364
Published
Nov 17, 2023
Updated
Aug 29, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, CWE-1333, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 2024Record 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

5.0GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L
5.3Adobe Systems IncorporatedCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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 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 exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-1333Inefficient Regular Expression Complexity
T1499Endpoint Denial of Service

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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