CVE-2026-104587

Status: DeferredMedium (5.4)—PoC

Severity5.4Medium · CVSS 3.1

Exploitation probability0.21 %higher than 10% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitAvailableProof of concept on GitHub (unverified)

blob42 gosuki through commit 6e2bf34 contains a Stored Cross-Site Scripting (XSS) vulnerability. The application uses text/template instead of html/template, failing to perform context-aware auto-escaping on the URL and DisplayURL fields of bookmarks in internal/webui/templates/bookmarks.html. An attacker can craft a malicious bookmark URL containing HTML attribute-breaking payloads that execute arbitrary JavaScript in the victim's browser context when rendered in the local web interface.

CVSS

Base score: 5.4
Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.21 %
Percentile among all scored CVEs: 10
Score date: 10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Proof of concept on GitHub (unverified) · List of proofs of concept on GitHub

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1189 Drive-by Compromiseinitial access90 %
Primary impactT1059.007 JavaScriptexecution85 %

XSS almacenado (CWE-79) por usar text/template sin escape contextual en URL de marcadores; el texto indica JavaScript ejecutado en el navegador de la víctima y el vector exige UI:R.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

ATT&CK mitigations that cover these techniques

Restrict Web-Based Content User Training Execution Prevention Behavior Prevention on Endpoint Disable or Remove Feature or Program Application Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Blob42 — Gosuki^AI

CWEs

CWE-79

References

Show 3 references

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-104587",
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  "metrics": {
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          "role": "CISA Coordinator",
          "options": [
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              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-15T14:47:42.601854Z"
        }
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    "cvssMetricV31": [
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        "cvssData": {
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          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
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  "published": "2026-10-13T21:17:25.703",
  "references": [
    {
      "url": "https://github.com/AmalJafarzade/CVE-2026-104587",
      "source": "cve@mitre.org"
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    {
      "url": "https://github.com/blob42/gosuki",
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    {
      "lang": "en",
      "value": "blob42 gosuki through commit 6e2bf34 contains a Stored Cross-Site Scripting (XSS) vulnerability. The application uses text/template instead of html/template, failing to perform context-aware auto-escaping on the URL and DisplayURL fields of bookmarks in internal/webui/templates/bookmarks.html. An attacker can craft a malicious bookmark URL containing HTML attribute-breaking payloads that execute arbitrary JavaScript in the victim's browser context when rendered in the local web interface."
    }
  ],
  "lastModified": "2026-10-16T19:56:15.773",
  "sourceIdentifier": "cve@mitre.org"
}