How severe is CVE-2015-8766?

CVE-2015-8766 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which products are affected by CVE-2015-8766?

Affected package information for CVE-2015-8766 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2015-8766?

No patch has shipped for CVE-2015-8766 yet — track the getsymphony symphony advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2015-8766 across my infrastructure?

Inventory every getsymphony symphony deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2015-8766 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2015-8766?

O3 detects and blocks CVE-2015-8766 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2015-8766 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2015-8766, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2015-8766?

CVE-2015-8766 has an EPSS (Exploit Prediction Scoring System) score of 1.8%, placing it in the 75th 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-2015-8766?

CVE-2015-8766 is classified as Cross-site Scripting (XSS) (CWE-79). 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.

Which products and versions are affected by CVE-2015-8766?

CVE-2015-8766 affects getsymphony symphony. Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2015-8766 published, and has it been updated?

CVE-2015-8766 was published on January 8, 2016 and was last updated on June 17, 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-2015-8766: Symphony Cross-site Scripting (XSS) (Medium 6.1)

EPSS Exploitation Probability

via FIRST.org ↗

1.8%probability of exploitation in next 30 days

Lower Risk75th percentile+1.49%

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.

Description

Multiple cross-site scripting (XSS) vulnerabilities in content/content.systempreferences.php in Symphony CMS before 2.6.4 allow remote attackers to inject arbitrary web script or HTML via the (1) email_sendmail[from_name], (2) email_sendmail[from_address], (3) email_smtp[from_name], (4) email_smtp[from_address], (5) email_smtp[host], (6) email_smtp[port], (7) jit_image_manipulation[trusted_external_sites], or (8) maintenance_mode[ip_whitelist] parameters to system/preferences.

Affected Products

1 product · 1 configurations

Application

symphonygetsymphony

≤ 2.6.3

range

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every getsymphony symphony deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2015-8766 yet — track the getsymphony symphony advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2015-8766 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2015-8766. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Multiple cross-site scripting (XSS) vulnerabilities in content/content.systempreferences.php in Symphony CMS before 2.6.4 allow remote attackers to inject arbitrary web script or HTML via the (1) email_sendmail[from_name], (2) email_sendmail[from_address], (3) email_smtp[from_name], (4) email_smtp[from_address], (5) email_smtp[host], (6) email_smtp[port], (7) jit_image_manipulation[trusted_external_sites], or (8) maintenance_mode[ip_whitelist] parameters to system/preferences.

O3 Security · Runtime Protection

Is CVE-2015-8766 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2015-8766 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.

Protect my workloads How runtime protection works

CVE-2015-8766

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

How O3 protects you

Frequently Asked Questions

Is CVE-2015-8766 being exploited in your environment?