Vulnerability-Lookup

GHSA-JM8C-9F3J-4378

Vulnerability from github – Published: 2026-04-18 01:11 – Updated: 2026-06-08 19:03

Summary

pretalx mail templates vulnerable to email injection via unescaped user-controlled placeholders

Details

An unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance's configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim's email address, and triggers a password reset. The resulting email is delivered from the event's legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector.

The same class of bug affects every mail template that interpolates a user-controlled placeholder (speaker name, proposal title, biography, question answers, etc.), including organiser-triggered emails such as acceptance/rejection notifications.

Credits

Thanks go to Mark Fijneman for finding and reporting a subset of this issue, which alerted us to the wider vulnerability.

Severity

6.1 (Medium)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pretalx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41426"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-116",
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-18T01:11:19Z",
    "nvd_published_at": "2026-04-24T20:16:27Z",
    "severity": "MODERATE"
  },
  "details": "An unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance\u0027s configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim\u0027s email address, and triggers a password reset. The resulting email is delivered from the event\u0027s legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector.\n\nThe same class of bug affects every mail template that interpolates a user-controlled placeholder (speaker name, proposal title, biography, question answers, etc.), including organiser-triggered emails such as acceptance/rejection notifications.\n\n### Credits\n\nThanks go to Mark Fijneman for finding and reporting a subset of this issue, which alerted us to the wider vulnerability.",
  "id": "GHSA-jm8c-9f3j-4378",
  "modified": "2026-06-08T19:03:12Z",
  "published": "2026-04-18T01:11:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41426"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pretalx/pretalx"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/pretalx/PYSEC-2026-109.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "pretalx mail templates vulnerable to email injection via unescaped user-controlled placeholders"
}

CVE-2026-41426 (GCVE-0-2026-41426)

Vulnerability from cvelistv5 – Published: 2026-04-24 19:15 – Updated: 2026-04-25 01:50

Title

pretalx: Email injection via unescaped user-controlled placeholders in pretalx mail templates

Summary

pretalx is a conference planning tool. Prior to 2026.1.0, an unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance's configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim's email address, and triggers a password reset. The resulting email is delivered from the event's legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector. This vulnerability is fixed in 2026.1.0.

Severity

6.1 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-25 01:50 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116 - Improper Encoding or Escaping of Output

Assigner

GitHub_M mitre root Scorecard

References

1 reference

URL	Tags
https://github.com/pretalx/pretalx/security/advis…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
pretalx	pretalx	Affected: < 2026.1.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-41426",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-25T01:50:24.719547Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-25T01:50:38.208Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "pretalx",
          "vendor": "pretalx",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2026.1.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "pretalx is a conference planning tool. Prior to 2026.1.0, an unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance\u0027s configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim\u0027s email address, and triggers a password reset. The resulting email is delivered from the event\u0027s legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector. This vulnerability is fixed in 2026.1.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.1,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-116",
              "description": "CWE-116: Improper Encoding or Escaping of Output",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-24T19:15:39.205Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378"
        }
      ],
      "source": {
        "advisory": "GHSA-jm8c-9f3j-4378",
        "discovery": "UNKNOWN"
      },
      "title": "pretalx: Email injection via unescaped user-controlled placeholders in pretalx mail templates"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-41426",
    "datePublished": "2026-04-24T19:15:39.205Z",
    "dateReserved": "2026-04-20T15:32:33.814Z",
    "dateUpdated": "2026-04-25T01:50:38.208Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

PYSEC-2026-109

Vulnerability from pysec - Published: 2026-04-24 20:16 - Updated: 2026-05-20 09:19

Details

Severity

6.1 (Medium)


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

Impacted products

Name	purl
pretalx	pkg:pypi/pretalx

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pretalx",
        "purl": "pkg:pypi/pretalx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.0",
        "0.2.0.post1",
        "0.2.1.post1",
        "0.2.2",
        "0.3.0",
        "0.3.1",
        "0.4.0",
        "0.4.1",
        "0.5.0",
        "0.6.0",
        "0.6.1",
        "0.7.0",
        "0.7.1",
        "0.8.0",
        "0.9.0",
        "1.0.0",
        "1.0.1",
        "1.0.2",
        "1.0.3",
        "1.0.4",
        "1.1.0",
        "1.1.1",
        "1.1.2",
        "2.0.0",
        "2.1.0",
        "2.1.1",
        "2.2.0",
        "2.3.0",
        "2.3.1",
        "2.3.2",
        "2023.1.0",
        "2023.1.1",
        "2023.1.2",
        "2023.1.3",
        "2024.1.0",
        "2024.2.0",
        "2024.2.1",
        "2024.3.0",
        "2024.3.1",
        "2025.1.0",
        "2025.2.0",
        "2025.2.1",
        "2025.2.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41426",
    "GHSA-jm8c-9f3j-4378"
  ],
  "details": "pretalx is a conference planning tool. Prior to 2026.1.0, an unauthenticated attacker can send arbitrary HTML-rendered emails from a pretalx instance\u0027s configured sender address by embedding malformed HTML or markdown link syntax in a user-controlled template placeholder such as the account display name. The most direct vector is the password-reset flow: the attacker registers an account with a malicious name, enters the victim\u0027s email address, and triggers a password reset. The resulting email is delivered from the event\u0027s legitimate sender address and passes SPF/DKIM/DMARC validation, making it a ready-made phishing vector. This vulnerability is fixed in 2026.1.0.",
  "id": "PYSEC-2026-109",
  "modified": "2026-05-20T09:19:11.385949Z",
  "published": "2026-04-24T20:16:27.247Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-JM8C-9F3J-4378

Credits

CVE-2026-41426 (GCVE-0-2026-41426)

PYSEC-2026-109

Tags

Sightings

Nomenclature

Related by attack behaviour