Vulnerability-Lookup

FKIE_CVE-2026-1721

Vulnerability from fkie_nvd - Published: 2026-02-13 03:15 - Updated: 2026-04-15 00:35

Severity ?

6.2 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N

Summary

Summary A Reflected Cross-Site Scripting (XSS) vulnerability was discovered in the AI Playground's OAuth callback handler. The `error_description` query parameter was directly interpolated into an HTML script tag without proper escaping, allowing attackers to execute arbitrary JavaScript in the context of the victim's session. Root cause The OAuth callback handler in `site/ai-playground/src/server.ts` directly interpolated the `authError` value, sourced from the `error_description` query parameter, into an inline `<script>` tag. Impact An attacker could craft a malicious link that, when clicked by a victim, would: * Steal user chat message history - Access all LLM interactions stored in the user's session. * Access connected MCP Servers - Interact with any MCP servers connected to the victim's session (public or authenticated/private), potentially allowing the attacker to perform actions on the victim's behalf Mitigation: * PR: https://github.com/cloudflare/agents/pull/841 https://github.com/cloudflare/agents/pull/841 * Agents-sdk users should upgrade to agents@0.3.10 * Developers using configureOAuthCallback with custom error handling in their own applications should ensure all user-controlled input is escaped before interpolation.

References

	URL	Tags
	cna@cloudflare.com	https://github.com/cloudflare/agents/pull/841

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Summary\n\nA Reflected Cross-Site Scripting (XSS) vulnerability was discovered in the AI Playground\u0027s OAuth callback handler. The `error_description` query parameter was directly interpolated into an HTML script tag without proper escaping, allowing attackers to execute arbitrary JavaScript in the context of the victim\u0027s session.\n\n\n\n\nRoot cause\n\nThe OAuth callback handler in `site/ai-playground/src/server.ts` directly interpolated the `authError` value, sourced from the `error_description` query parameter,  into an inline `\u003cscript\u003e` tag.\n\n\nImpact\n\nAn attacker could craft a malicious link that, when clicked by a victim, would:\n\n  *  Steal user chat message history - Access all LLM interactions stored in the user\u0027s session.\n\n\n  *  Access connected MCP Servers - Interact with any MCP servers connected to the victim\u0027s session (public or authenticated/private), potentially allowing the attacker to perform actions on the victim\u0027s behalf\n\n\n\n\n\nMitigation:\n\n  *  PR:\u00a0 https://github.com/cloudflare/agents/pull/841 https://github.com/cloudflare/agents/pull/841 \n\n\n\n\n  *  Agents-sdk users should upgrade to\u00a0agents@0.3.10\n\n\n\n\n  *  Developers using configureOAuthCallback with custom error handling in their own applications should ensure all user-controlled input is escaped before interpolation."
    },
    {
      "lang": "es",
      "value": "Resumen\n\nUna vulnerabilidad de Cross-Site Scripting Reflejado (XSS) fue descubierta en el manejador de callback de OAuth del AI Playground. El par\u00e1metro de consulta `error_description` fue directamente interpolado en una etiqueta de script HTML sin el escape adecuado, permitiendo a los atacantes ejecutar JavaScript arbitrario en el contexto de la sesi\u00f3n de la v\u00edctima.\n\nCausa ra\u00edz\n\nEl manejador de callback de OAuth en `site/ai-playground/src/server.ts` interpol\u00f3 directamente el valor `authError`, obtenido del par\u00e1metro de consulta `error_description`, en una etiqueta `"
    }
  ],
  "id": "CVE-2026-1721",
  "lastModified": "2026-04-15T00:35:42.020",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.2,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "HIGH",
          "subIntegrityImpact": "LOW",
          "userInteraction": "ACTIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cna@cloudflare.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-02-13T03:15:52.467",
  "references": [
    {
      "source": "cna@cloudflare.com",
      "url": "https://github.com/cloudflare/agents/pull/841"
    }
  ],
  "sourceIdentifier": "cna@cloudflare.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}

CVE-2026-1721 (GCVE-0-2026-1721)

Vulnerability from cvelistv5 – Published: 2026-02-13 01:46 – Updated: 2026-02-27 14:51

Title

Reflected Cross-Site Scripting (XSS) vulnerability in AI Playground site

Summary

Severity ?

6.2 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

cloudflare

References

URL

Tags

https://github.com/cloudflare/agents/pull/841

Impacted products

	Vendor	Product	Version
			Affected: 0 , < 0.3.10 (git)

Credits

Nishant Kumawat

Show details on NVD website

JSON

To clipboard

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                "id": "CVE-2026-1721",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-13T13:10:24.218273Z",
                "version": "2.0.3"
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              "type": "ssvc"
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        "problemTypes": [
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            "descriptions": [
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                "cweId": "CWE-79",
                "description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
                "lang": "en",
                "type": "CWE"
              }
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        "providerMetadata": {
          "dateUpdated": "2026-02-27T14:51:31.817Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/cloudflare",
          "defaultStatus": "unaffected",
          "packageName": "agents",
          "repo": "https://github.com/cloudflare/agents",
          "versions": [
            {
              "lessThan": "0.3.10",
              "status": "affected",
              "version": "0",
              "versionType": "git"
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      "credits": [
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          "lang": "en",
          "type": "reporter",
          "value": "Nishant Kumawat"
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      "descriptions": [
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              "value": "\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003e\u003cb\u003eSummary\u003c/b\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eA Reflected Cross-Site Scripting (XSS) vulnerability was discovered in the AI Playground\u0027s OAuth callback handler. The `error_description` query parameter was directly interpolated into an HTML script tag without proper escaping, allowing attackers to execute arbitrary JavaScript in the context of the victim\u0027s session.\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003e\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003e\u003cb\u003eRoot cause\u003c/b\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eThe OAuth callback handler in `site/ai-playground/src/server.ts` directly interpolated the `authError` value, sourced from the `error_description` query parameter,  into an inline `\u0026lt;script\u0026gt;` tag.\u003c/span\u003e\u003c/p\u003e\u003cb\u003e\u003cbr\u003e\u003c/b\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003e\u003cb\u003eImpact\u003c/b\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eAn attacker could craft a malicious link that, when clicked by a victim, would:\u003c/span\u003e\u003c/p\u003e\u003col\u003e\u003cli\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eSteal user chat message history - Access all LLM interactions stored in the user\u0027s session.\u003c/span\u003e\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eAccess connected MCP Servers - Interact with any MCP servers connected to the victim\u0027s session (public or authenticated/private), potentially allowing the attacker to perform actions on the victim\u0027s behalf\u003c/span\u003e\u003c/p\u003e\u003c/li\u003e\u003c/ol\u003e\u003cdiv\u003e\u003cb\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003e\u003cbr\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eMitigation:\u003c/span\u003e\u003c/p\u003e\u003c/b\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003ePR:\u0026nbsp;\u003c/span\u003e\u003ca target=\"_blank\" rel=\"nofollow\" href=\"https://github.com/cloudflare/agents/pull/841\"\u003e\u003cspan style=\"background-color: transparent;\"\u003ehttps://github.com/cloudflare/agents/pull/841\u003c/span\u003e\u003c/a\u003e\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eAgents-sdk users should upgrade to\u0026nbsp;\u003c/span\u003e\u003cspan style=\"background-color: transparent;\"\u003eagents@0.3.10\u003c/span\u003e\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cspan style=\"background-color: transparent;\"\u003eDevelopers using configureOAuthCallback with custom error handling in their own applications should ensure all user-controlled input is escaped before interpolation.\u003c/span\u003e\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/div\u003e\u003cbr\u003e"
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            "Recovery": "NOT_DEFINED",
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            "baseScore": 6.2,
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          "url": "https://github.com/cloudflare/agents/pull/841"
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    "assignerShortName": "cloudflare",
    "cveId": "CVE-2026-1721",
    "datePublished": "2026-02-13T01:46:48.674Z",
    "dateReserved": "2026-01-30T20:12:22.668Z",
    "dateUpdated": "2026-02-27T14:51:31.817Z",
    "state": "PUBLISHED"
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Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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FKIE_CVE-2026-1721

CVE-2026-1721 (GCVE-0-2026-1721)

Tags

Sightings

Nomenclature