How severe is CVE-2026-100391?

No CVSS score has been assigned to CVE-2026-100391 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-100391?

Affected package information for CVE-2026-100391 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-100391?

Upgrade the affected component to the fixed release for CVE-2026-100391, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.

How do I detect CVE-2026-100391 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-100391 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-100391 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-100391 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-2026-100391?

CVE-2026-100391 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th 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.

What type of vulnerability is CVE-2026-100391?

CVE-2026-100391 is classified as Server-Side Request Forgery (SSRF) (CWE-918). 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.

When was CVE-2026-100391 published, and has it been updated?

CVE-2026-100391 was published on September 25, 2026 and was last updated on October 7, 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-2026-100391: mediaflow-proxy SSRF

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-100391.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

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

Description

MediaFlow Proxy through 2.4.9 contains a server-side request forgery vulnerability in the /proxy routes due to missing and incomplete destination validation in the d query parameter. Remote attackers can supply arbitrary internal URLs including loopback and cloud metadata endpoints to read full responses from the proxy server.

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2026-100391, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

MediaFlow Proxy through 2.4.9 contains a server-side request forgery vulnerability in the /proxy routes due to missing and incomplete destination validation in the d query parameter. Remote attackers can supply arbitrary internal URLs including loopback and cloud metadata endpoints to read full responses from the proxy server.

O3 Security · Impact-Aware SCA

Is CVE-2026-100391 in your dependencies?

Find it across , including transitive dependencies.

Scan my dependencies How O3 SCA works

CVE-2026-100391 — mediaflow-proxy