How severe is CVE-2026-91353?

CVE-2026-91353 has a CVSS score of 8.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-91353?

Affected package information for CVE-2026-91353 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-91353?

No fixed release is recorded for CVE-2026-91353 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2026-91353 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-2026-91353 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.

Is CVE-2026-91353 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-91353 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-2026-91353?

CVE-2026-91353 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th 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-2026-91353 published, and has it been updated?

CVE-2026-91353 was published on October 20, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

Not in CISA KEV

HIGH severity

CVE-2026-91353 — Oracle

HIGH

CVE-2026-91353 is a high-severity (CVSS 8.6) vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

Vulnerability in the Oracle Outside In Technology product of Oracle Fusion Middleware (component: Outside In Clean Content SDK). The supported version that is affected is 8.5.8. Easily…

Published

Oct 20, 2026

Updated

Oct 21, 2026

Affected

—

Patched

—

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2026-91353 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Vulnerability in the Oracle Outside In Technology product of Oracle Fusion Middleware (component: Outside In Clean Content SDK). The supported version that is affected is 8.5.8. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Oracle Outside In Technology. While the vulnerability is in Oracle Outside In Technology, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle Outside In Technology accessible data. CVSS 3.1 Base Score 8.6 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N).

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`).
Remediation status
No fixed release is recorded for CVE-2026-91353 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
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.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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