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Not in CISA KEV
HIGH severity

CVE-2021-41500 — cvxopt

HIGHFix: cvxopt/cvxopt@d5a21cf

CVE-2021-41500 is a high-severity (CVSS 7.5) CWE-697 vulnerability in cvxopt. 1 public exploit reference exists, so weaponization risk is real. A fix is available for cvxopt — see the affected versions and patch details below.

Incorrect Comparison in cvxopt

Also known asGHSA-8rh6-h94m-vj54PYSEC-2021-870
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk
0.00%0.56%1.12%1.68%0.3%1.2%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-41500 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍cvxopt

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

Incomplete string comparison vulnerability exits in cvxopt.org cvxop <= 1.2.6 in APIs (cvxopt.cholmod.diag, cvxopt.cholmod.getfactor, cvxopt.cholmod.solve, cvxopt.cholmod.spsolve), which allows attackers to conduct Denial of Service attacks by construct fake Capsule objects.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIcvxoptall versions1.2.7pip install --upgrade 'cvxopt==1.2.7'

Affected Products

2 products · 2 configurations
Application
cvxoptcvxopt_project
≤ 1.2.6
range
OS
fedorafedoraproject
1 version
34
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Incomplete string comparison vulnerability exits in cvxopt.org cvxop <= …

github.comNVDDec 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update cvxopt to 1.2.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41500 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

Incomplete string comparison vulnerability exits in cvxopt.org cvxop <= 1.2.6 in APIs (cvxopt.cholmod.diag, cvxopt.cholmod.getfactor, cvxopt.cholmod.solve, cvxopt.cholmod.spsolve), which allows attackers to conduct Denial of Service attacks by construct fake Capsule objects.
O3 Security · Impact-Aware SCA

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Find it across PyPI, including transitive dependencies.

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CVE-2021-41500: cvxopt DoS — Fixed in 1.2.7