How severe is CVE-2021-40323?

CVE-2021-40323 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-40323?

CVE-2021-40323 affects the following packages: cobbler (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2021-40323?

Update cobbler to 3.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40323 is resolved across your whole dependency graph.

How do I detect CVE-2021-40323 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cobbler, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-40323 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2021-40323 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-40323 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-40323?

CVE-2021-40323 has an EPSS (Exploit Prediction Scoring System) score of 86.8%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-40323?

CVE-2021-40323 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2021-40323?

A Nuclei detection template exists for CVE-2021-40323, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-40323 published, and has it been updated?

CVE-2021-40323 was published on October 4, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

CRITICAL severity

CVE-2021-40323 — cobbler

CRITICALFix: cobbler/cobbler@d8f60bb

CVE-2021-40323 is a critical-severity (CVSS 9.8) Code Injection vulnerability in cobbler. EPSS puts its 30-day exploitation probability at 86.8% (100th percentile). A fix is available for cobbler — see the affected versions and patch details below.

Cobbler before 3.3.0 allows log poisoning

Also known asGHSA-cpqf-3c3r-c9g2PYSEC-2021-373

Published

Oct 4, 2021

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

86.8%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-40323 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐍cobbler

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Cobbler before 3.3.0 allows log poisoning, and resultant Remote Code Execution, via an XMLRPC method that logs to the logfile for template injection.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`cobbler`	all versions	3.3.0`pip install --upgrade 'cobbler==3.3.0'`

Affected Products

1 product · 1 configurations

Application

cobblercobbler_project

≤ 3.3.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cobbler, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cobbler to 3.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40323 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

How to detect CVE-2021-40323

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-40323 -u https://target

Template: Cobbler <3.3.0 - Remote Code Execution
Severity: critical
Impact: Successful exploitation of this vulnerability can lead to unauthorized remote code execution, potentially resulting in complete compromise of the affected system.
Remediation: Upgrade Cobbler to version 3.3.0 or later, which includes a fix for this vulnerability.

Template by ProjectDiscovery nuclei-templates (c-sh0), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

Cobbler before 3.3.0 allows log poisoning, and resultant Remote Code Execution, via an XMLRPC method that logs to the logfile for template injection.

O3 Security · Impact-Aware SCA

Is CVE-2021-40323 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

9.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE Classification

Weaponization

OpenSSF Scorecard

Package health score

cobbler

5.7/10

Maintained10/10

Code-Review0/10

Branch-ProtectionN/A

Assessed Sep 28, 2026

Timeline

Disclosed

Oct 4, 2021

Last updated

Jul 9, 2026

Identifiers

CVE-2021-40323

GHSA-cpqf-3c3r-c9g2

PYSEC-2021-373

References

Advisorygithub.com Advisorynvd.nist.gov Advisorygithub.com Fixgithub.com Webgithub.com Packagegithub.com

Related vulnerabilities

This CVE is critical severity; 2 of 8 other CVEs affecting cobbler are rated as high or higher (top: critical).

CVE-2024-47533CVE-2012-2395CVE-2011-4953CVE-2010-2235CVE-2008-6954CVE-2017-1000469CVE-2018-1000225CVE-2014-3225

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 9, 2026

CVE-2021-40323 — cobbler

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

How to detect CVE-2021-40323

Frequently Asked Questions

Is CVE-2021-40323 in your dependencies?