Vulnerability-Lookup

GHSA-JM8C-9F3J-4378

Vulnerability from github – Published: 2026-04-18 01:11 – Updated: 2026-04-18 01:11

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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pretalx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-116",
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-18T01:11:19Z",
    "nvd_published_at": null,
    "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": "2026-04-18T01:11:19Z",
  "published": "2026-04-18T01:11:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pretalx/pretalx/security/advisories/GHSA-jm8c-9f3j-4378"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pretalx/pretalx"
    }
  ],
  "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

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

References

URL

Tags

https://github.com/pretalx/pretalx/security/advis…

x_refsource_CONFIRM

Impacted products

	Vendor	Product	Version
	pretalx	pretalx	Affected: < 2026.1.0

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-41426",
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                  },
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                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-25T01:50:24.719547Z",
                "version": "2.0.3"
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        }
      ],
      "metrics": [
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          "cvssV3_1": {
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            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
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            "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",
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      "problemTypes": [
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      "providerMetadata": {
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      "source": {
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        "discovery": "UNKNOWN"
      },
      "title": "pretalx: Email injection via unescaped user-controlled placeholders in pretalx mail templates"
    }
  },
  "cveMetadata": {
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    "dateReserved": "2026-04-20T15:32:33.814Z",
    "dateUpdated": "2026-04-25T01:50:38.208Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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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