CVE-2019-25091 is a medium-severity (CVSS 5.3) CWE-1004 vulnerability in nsupdate. No vendor fix is recorded yet; mitigation options are listed below.
nsupdate.info has Sensitive Cookie Without 'HttpOnly' Flag
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-2019-25091 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
nsupdateReal-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
A vulnerability classified as problematic has been found in nsupdate.info. This affects an unknown part of the file src/nsupdate/settings/base.py of the component CSRF Cookie Handler. The manipulation of the argument CSRF_COOKIE_HTTPONLY leads to cookie without 'httponly' flag. It is possible to initiate the attack remotely. The name of the patch is 60a3fe559c453bc36b0ec3e5dd39c1303640a59a. It is recommended to apply a patch to fix this issue. The identifier VDB-216909 was assigned to this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | nsupdate | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nsupdate, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of nsupdate has shipped for CVE-2019-25091 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2019-25091 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2019-25091. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2019-25091 in your dependencies?
O3 Security finds CVE-2019-25091 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.