Vulnerability-Lookup

GHSA-R26J-82CG-5H6C

Vulnerability from github – Published: 2026-08-15 03:30 – Updated: 2026-08-15 03:30

Details

The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The synchronize_session() function, hooked on init and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied ussync-key, ussync-token, and ussync-ref parameters; when ussync-key references an unregistered slot, get_option() returns false for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable md5('') and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as md5('another-secret'). This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the ussync-ref parameter, causing the handler to call wp_set_auth_cookie() for the matched user and granting full authentication as that user — including administrators — with no prior knowledge of site secrets.

Severity

9.8 (Critical)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-15341"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T03:16:47Z",
    "severity": "CRITICAL"
  },
  "details": "The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5(\u0027\u0027)` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5(\u0027another-secret\u0027)`. This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user \u2014 including administrators \u2014 with no prior knowledge of site secrets.",
  "id": "GHSA-r26j-82cg-5h6c",
  "modified": "2026-08-15T03:30:24Z",
  "published": "2026-08-15T03:30:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15341"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L117"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L286"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L310"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L422"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L598"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L631"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/cbc32e6d-47c5-4050-ba77-5a54203fe56a?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-15341 (GCVE-0-2026-15341)

Vulnerability from cvelistv5 – Published: 2026-08-15 02:26 – Updated: 2026-08-17 15:55

Title

User Session Synchronizer <= 1.4.0 - Unauthenticated Authentication Bypass to Account Takeover via 'ussync-key', 'ussync-token', and 'ussync-ref' Parameters

Summary

The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5('')` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5('another-secret')`. This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user — including administrators — with no prior knowledge of site secrets.

Severity

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-17 15:55 UTC

CWE

CWE-287 - Improper Authentication

Assigner

Wordfence mitre root

References

7 references

URL	Tags
https://www.wordfence.com/threat-intel/vulnerabil…
https://plugins.trac.wordpress.org/browser/user-s…
https://plugins.trac.wordpress.org/browser/user-s…
https://plugins.trac.wordpress.org/browser/user-s…
https://plugins.trac.wordpress.org/browser/user-s…
https://plugins.trac.wordpress.org/browser/user-s…
https://plugins.trac.wordpress.org/browser/user-s…

Impacted products

1 product

Vendor	Product	Version
rafasashi	User Session Synchronizer	Affected: 0 , ≤ 1.4.0 (semver)

Credits

Afan moonge

Show details on NVD website

JSON

To clipboard

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  "containers": {
    "adp": [
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        "metrics": [
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              "content": {
                "id": "CVE-2026-15341",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-17T15:55:26.708943Z",
                "version": "2.0.3"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
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      }
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    "cna": {
      "affected": [
        {
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          "product": "User Session Synchronizer",
          "vendor": "rafasashi",
          "versions": [
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              "lessThanOrEqual": "1.4.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
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      "credits": [
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          "type": "finder",
          "value": "Afan"
        },
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          "lang": "en",
          "type": "finder",
          "value": "moonge"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5(\u0027\u0027)` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5(\u0027another-secret\u0027)`. This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user \u2014 including administrators \u2014 with no prior knowledge of site secrets."
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      "metrics": [
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      },
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          "url": "https://plugins.trac.wordpress.org/browser/user-session-synchronizer/tags/1.4.0/includes/class-user-session-synchronizer.php#L422"
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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.

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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GHSA-R26J-82CG-5H6C

CVE-2026-15341 (GCVE-0-2026-15341)

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