Vulnerability-Lookup

GHSA-52JG-6VW4-42P8

Vulnerability from github – Published: 2026-07-24 12:30 – Updated: 2026-07-24 12:30

Details

Apereo CAS Client accepts any CA-trusted certificate for any hostname, provided the URL the client is calling matches the configured allowlist or regex. An attacker with a MITM position (DNS poisoning, rogue Wi-Fi, malicious proxy, etc.) can provide any CA-signed certificate for a hostname that matches the configured allowlist or regex. This can lead to intercepting the CAS exchange, capturing the Ticket-Granting Ticket (TGT), and subsequently obtaining Service Tickets on behalf of the victim.

Because maintainers contact attempts were unsuccessful, vulnerabilities have only been confirmed in version 4.1.0 (Java Apereo CAS Client) and 3.6.4 (Jasig CAS Client) but may also affect other versions.

Severity

7.4 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-15243"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-297"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-24T12:16:46Z",
    "severity": "HIGH"
  },
  "details": "Apereo CAS Client\u00a0accepts any CA-trusted certificate for any hostname, provided the URL the client is calling matches the configured allowlist or regex. An attacker with a MITM position (DNS poisoning, rogue Wi-Fi, malicious proxy, etc.) can provide any CA-signed certificate for a hostname that matches the configured allowlist or regex. This can lead to\u00a0intercepting the CAS exchange, capturing the\u00a0Ticket-Granting Ticket (TGT), and subsequently obtaining Service Tickets on behalf of the victim.\u00a0\n\n\nBecause maintainers contact attempts were unsuccessful, vulnerabilities have only been confirmed in version 4.1.0 (Java Apereo CAS Client) and\u00a03.6.4 (Jasig CAS Client) but may also affect other versions.",
  "id": "GHSA-52jg-6vw4-42p8",
  "modified": "2026-07-24T12:30:53Z",
  "published": "2026-07-24T12:30:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15243"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-15243"
    },
    {
      "type": "WEB",
      "url": "https://www.apereo.org/programs/software/cas"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-15243 (GCVE-0-2026-15243)

Vulnerability from cvelistv5 – Published: 2026-07-24 11:29 – Updated: 2026-07-24 12:33 X_Open Source

Title

Improper Validation of Certificate in CAS Client

Summary

Severity

7.4 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-24 12:33 UTC

CWE

CWE-297 - Improper validation of certificate with host mismatch

Assigner

CERT-PL ENISA root Scorecard

References

2 references

URL	Tags
https://cert.pl/en/posts/2026/07/CVE-2026-15243	third-party-advisory
https://www.apereo.org/programs/software/cas	product

Impacted products

2 products

Vendor	Product	Version
Apereo	Java Apereo CAS Client	Affected: 4.1.0 (semver)
Apereo	Jasig CAS Client	Affected: 3.6.4

Credits

Rafał Łykowski (Qualtrics) Łukasz Kollbek (Qualtrics) Krzysztof Surówka (Qualtrics)

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                  },
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                "timestamp": "2026-07-24T12:33:47.532505Z",
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          "packageName": "org.jasig.cas.client",
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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-52JG-6VW4-42P8

CVE-2026-15243 (GCVE-0-2026-15243)

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