Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.29% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-61791High confidence
OCO-Server: Stored XSS through agent hostnames in command buttons
schorschii · OCO-Server
Official source article: GitHub GHSA-9C2R-9J95-22PR ↗. Check the applicable product and release in the original source.
7.4HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs schorschii OCO-Server and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
OCO-Server is a self-hosted endpoint management application for computer inventory, software deployment, and mobile device management. Prior to 1.2.1, `Html::commandButton()` in `lib/Html.class.php` embeds an action URL containing a stored computer hostname into a JavaScript string in an inline `onclick` handler, using `htmlspecialchars(ENT_QUOTES)` only for HTML escaping. Browsers decode the HTML entities before interpreting the handler as JavaScript, allowing a crafted hostname to escape the string and execute script in an administrator's authenticated session when an affected command button is activated. `frontend/views/computer-details.php` passes `$computer->hostname` to this helper using `Computer::DEFAULT_COMPUTER_COMMANDS` in `lib/Models/Computer.class.php`, whose VNC, RDP, SSH, and Ping entries use `new_tab=false` and the vulnerable `window.location` branch. A remote attacker who possesses the shared `agent-registration-key` can use the `oco.agent.hello` handler in `frontend/api-agent.php` to store an unchecked hostname when `agent-self-registration-enabled` is enabled; self-registration is disabled by default. The vulnerable default command buttons require no custom command configuration. The injected script can abuse the administrator's privileges, including permission to deploy software jobs to managed computers. This issue is fixed in version 1.2.1.
What
OCO-Server is a self-hosted endpoint management application for computer inventory, software deployment, and mobile device management. Prior to 1.2.1, `Html::commandButton()` in `lib/Html.class.php` embeds an action URL containing a stored computer hostname into a JavaScript string in an inline `onclick` handler, using `htmlspecialchars(ENT_QUOTES)` only for HTML escaping. Browsers decode the HTML entities before interpreting the handler as JavaScript, allowing a crafted hostname to escape the string and execute script in an administrator's authenticated session when an affected command button is activated. `frontend/views/computer-details.php` passes `$computer->hostname` to this helper using `Computer::DEFAULT_COMPUTER_COMMANDS` in `lib/Models/Computer.class.php`, whose VNC, RDP, SSH, and Ping entries use `new_tab=false` and the vulnerable `window.location` branch. A remote attacker who possesses the shared `agent-registration-key` can use the `oco.agent.hello` handler in `frontend/api-agent.php` to store an unchecked hostname when `agent-self-registration-enabled` is enabled; self-registration is disabled by default. The vulnerable default command buttons require no custom command configuration. The injected script can abuse the administrator's privileges, including permission to deploy software jobs to managed computers. This issue is fixed in version 1.2.1.
Why
The product does not neutralize or incorrectly neutralizes javascript: or other URIs from dangerous attributes within tags, such as onmouseover, onload, onerror, or style.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
OCO-Server is a self-hosted endpoint management application for computer inventory, software deployment, and mobile device management. Prior to 1.2.1, `Html::commandButton()` in `lib/Html.class.php` embeds an action URL containing a stored computer hostname into a JavaScript string in an inline `onclick` handler, using `htmlspecialchars(ENT_QUOTES)` only for HTML escaping. Browsers decode the HTML entities before interpreting the handler as JavaScript, allowing a crafted hostname to escape the string and execute script in an administrator's authenticated session when an affected command button is activated. `frontend/views/computer-details.php` passes `$computer->hostname` to this helper using `Computer::DEFAULT_COMPUTER_COMMANDS` in `lib/Models/Computer.class.php`, whose VNC, RDP, SSH, and Ping entries use `new_tab=false` and the vulnerable `window.location` branch. A remote attacker who possesses the shared `agent-registration-key` can use the `oco.agent.hello` handler in `frontend/api-agent.php` to store an unchecked hostname when `agent-self-registration-enabled` is enabled; self-registration is disabled by default. The vulnerable default command buttons require no custom command configuration. The injected script can abuse the administrator's privileges, including permission to deploy software jobs to managed computers. This issue is fixed in version 1.2.1.
Why
The product does not neutralize or incorrectly neutralizes javascript: or other URIs from dangerous attributes within tags, such as onmouseover, onload, onerror, or style.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Improper Neutralization of Script in Attributes in a Web Page → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Required interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-83 ↗
CWE-83: Improper Neutralization of Script in Attributes in a Web Page. The product does not neutralize or incorrectly neutralizes javascript: or other URIs from dangerous attributes within tags, such as onmouseover, onload, onerror, or style.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:NCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.ANoneAvailability impact: No direct loss is represented by this metric.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Affected
- OCO-Server: < 1.2.1
- Fixed
- 1.2.1.
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 22 Oct 2026 · Last source change 22 Oct 2026, 14:55 UTC · CWE-83 · Improper Neutralization of Script in Attributes in a Web Page
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-10-23
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-108209
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- ENISA EUVD mappingEUVD-2026-108209 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-108209"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.