How severe is CVE-2026-28508?

No CVSS score has been assigned to CVE-2026-28508 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-28508?

CVE-2026-28508 affects the following packages: idno/known (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-28508?

Update idno/known to 1.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28508 is resolved across your whole dependency graph.

How do I detect CVE-2026-28508 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for idno/known. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-28508 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2026-28508?

O3 pinpoints whether CVE-2026-28508 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-28508 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28508 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-2026-28508?

CVE-2026-28508 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 45th 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. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2026-28508 published, and has it been updated?

CVE-2026-28508 was published on March 6, 2026 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-28508: Idno: Unauthenticated SSRF via URL Unfurl Endpo…

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk45th percentile+0.48%

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.

Blast Radius

1 pkg affected

🐘idno/known

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

Description

Idno is a social publishing platform. Prior to version 1.6.4, a logic error in the API authentication flow causes the CSRF protection on the URL unfurl service endpoint to be trivially bypassed by any unauthenticated remote attacker. Combined with the absence of a login requirement on the endpoint itself, this allows an attacker to force the server to make arbitrary outbound HTTP requests to any host, including internal network addresses and cloud instance metadata services, and retrieve the response content. This issue has been patched in version 1.6.4.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`idno/known`	all versions	1.6.4

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for idno/known. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update idno/known to 1.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28508 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 pinpoints whether CVE-2026-28508 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-28508. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Idno is a social publishing platform. Prior to version 1.6.4, a logic error in the API authentication flow causes the CSRF protection on the URL unfurl service endpoint to be trivially bypassed by any unauthenticated remote attacker. Combined with the absence of a login requirement on the endpoint itself, this allows an attacker to force the server to make arbitrary outbound HTTP requests to any host, including internal network addresses and cloud instance metadata services, and retrieve the response content. This issue has been patched in version 1.6.4.

O3 Security · Impact-Aware SCA

Is CVE-2026-28508 in your dependencies?

O3 detects CVE-2026-28508 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2026-28508