Vulnerability-Lookup

GHSA-8C8X-HFFR-47HM

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31

Details

A cross-site request forgery vulnerability in the OAuth extension of Zimbra Collaboration Suite (ZCS) Network Edition allows an attacker to link an attacker-controlled external account to a victim's mailbox. The OAuth callback does not bind its state value or authorization code to the initiating Zimbra session and instead selects the destination mailbox from the browser's current authentication cookie. On a deployment with the provider configured, an attacker can induce a signed-in victim to load a callback containing a fresh code for the attacker's provider account. This creates a persistent data source that imports attacker-controlled contacts or events. With bidirectional CalDAV synchronization, appointments subsequently created or edited in the linked calendar are also disclosed to the attacker. ZCS 10.1.16 and 10.1.20 are affected.

Severity

7.1 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93631"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T14:17:57Z",
    "severity": "HIGH"
  },
  "details": "A cross-site request forgery vulnerability in the OAuth extension of Zimbra Collaboration Suite (ZCS) Network Edition allows an attacker to link an attacker-controlled external account to a victim\u0027s mailbox. The OAuth callback does not bind its state value or authorization code to the initiating Zimbra session and instead selects the destination mailbox from the browser\u0027s current authentication cookie. On a deployment with the provider configured, an attacker can induce a signed-in victim to load a callback containing a fresh code for the attacker\u0027s provider account. This creates a persistent data source that imports attacker-controlled contacts or events. With bidirectional CalDAV synchronization, appointments subsequently created or edited in the linked calendar are also disclosed to the attacker. ZCS 10.1.16 and 10.1.20 are affected.",
  "id": "GHSA-8c8x-hffr-47hm",
  "modified": "2026-10-23T15:31:38Z",
  "published": "2026-10-23T15:31:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93631"
    },
    {
      "type": "WEB",
      "url": "https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"
    },
    {
      "type": "WEB",
      "url": "https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-93631 (GCVE-0-2026-93631)

Vulnerability from cvelistv5 – Published: 2026-10-23 13:23 – Updated: 2026-10-23 13:23

Title

Zimbra Collaboration Suite OAuth Extension Cross-Site Request Forgery Enables Account Linking

Summary

Severity

7.1 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

CWE

CWE-352 - Cross-Site request forgery (CSRF)

Assigner

rapid7 CNA under the mitre root

CNA scorecard B 76/100 over 81 records in the last 180 days details

References

2 references

URL	Tags
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories	vendor-advisory
https://www.rapid7.com/blog/post/ve-breaking-zimb…	related

Impacted products

1 product

Vendor	Product	Version
Zimbra	Zimbra Collaboration Suite	Affected: 0 , ≤ 10.1.20 (semver)

Date Public

2026-10-23 12:51

Credits

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7

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          "defaultStatus": "unaffected",
          "product": "Zimbra Collaboration Suite",
          "vendor": "Zimbra",
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              "lessThanOrEqual": "10.1.20",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
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        }
      ],
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          "lang": "en",
          "type": "finder",
          "value": "Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7"
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        }
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            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
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            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
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        "dateUpdated": "2026-10-23T13:23:34.952Z",
        "orgId": "9974b330-7714-4307-a722-5648477acda7",
        "shortName": "rapid7"
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      "references": [
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          "tags": [
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        },
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          "tags": [
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          "url": "https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"
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      "source": {
        "discovery": "UNKNOWN"
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    "dateReserved": "2026-09-18T12:22:34.911Z",
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    "state": "PUBLISHED"
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Sightings

Author	Source	Type	Date	Other

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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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