CVE-2023-26364 is a medium-severity (CVSS 5) Improper Input Validation vulnerability in @adobe/css-tools. A fix is available for @adobe/css-tools — see the affected versions and patch details below.
@adobe/css-tools Regular Expression Denial of Service (ReDOS) while Parsing CSS
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-26364.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-26364 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@adobe/css-toolsnpmDescription
Impact
@adobe/css-tools version 4.3.0 and earlier are affected by an Improper Input Validation vulnerability that could result in a denial of service while attempting to parse CSS.
Patches
The issue has been resolved in 4.3.1.
Workarounds
None
References
N/A
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @adobe/css-tools | all versions | 4.3.1npm install @adobe/css-tools@4.3.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @adobe/css-tools, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @adobe/css-tools to 4.3.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-26364 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-26364 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-26364. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Migration Toolkit for Runtimes 1 on RHEL 8 | mtr/mtr-operator-bundle:1.2-23 | RHSA-2024:3919 |
| MTA-6.2-RHEL-9 | mta/mta-windup-addon-rhel9:6.2.3-2 | RHSA-2024:3989 |
| MTA-7.0-RHEL-9 | mta/mta-cli-rhel9:7.0.3-16 | RHSA-2024:3316 |
| RHODF-4.14-RHEL-9 | odf4/odf-multicluster-console-rhel9:v4.14.13-3 | RHSA-2025:0323 |
| RHODF-4.15-RHEL-9 | odf4/odf-multicluster-console-rhel9:v4.15.9-1 | RHSA-2025:0164 |
| RHODF-4.16-RHEL-9 | odf4/odf-multicluster-console-rhel9:v4.16.5-2 | RHSA-2025:0082 |
| RHODF-4.17-RHEL-9 | odf4/odf-multicluster-console-rhel9:v4.17.0-53 | RHSA-2024:8676 |
Frequently Asked Questions
Is CVE-2023-26364 in your dependencies?
O3 Security finds CVE-2023-26364 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.