GHSA-mfxh-vp55-7gc6

Suggest an improvement
Source
https://github.com/advisories/GHSA-mfxh-vp55-7gc6
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-mfxh-vp55-7gc6/GHSA-mfxh-vp55-7gc6.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-mfxh-vp55-7gc6
Aliases
  • CVE-2026-107843
Published
2026-10-09T20:54:04Z
Modified
2026-10-09T21:00:10Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
Summary
Contao: The registration module re-sends activation mails
Details

ModuleRegistration::compile() reaches its follow-up registration branch on any POST to a page carrying the module. That branch checks neither FORM_SUBMIT nor the captcha result computed immediately above it, and resendActivationMail() leads to OptInToken::send(), which has no rate limit at all.

Impact

Anyone on the internet can make a Contao installation send unlimited mail to an address of their choosing, from the site's own sender and reputation, at one outbound message per HTTP request. That is both a nuisance for the recipient and a deliverability risk for the site operator. The same request is a reliable account oracle for "this address has a pending registration on this site", which is exactly the sort of membership fact a public site is usually expected not to disclose.

Honest bound. The target must have an unconfirmed registration, that is tl_member.disable = 1 together with an unconfirmed reg- opt-in token. An attacker can create that state for an arbitrary address, since registration requires no ownership proof, but on a site where reg_activate is off the branch is unreachable.

Database specific 
{
    "cwe_ids": [
        "CWE-204",
        "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-09T20:54:04Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
}
References

Affected packages

Packagist / contao/core-bundle

Package

Name
contao/core-bundle
Purl
pkg:composer/contao/core-bundle

Affected ranges

Type
ECOSYSTEM
Events
Introduced
4.1.0
Fixed
5.3.50

Affected versions

4.*
4.1.0
4.1.1
4.1.2
4.1.3
4.2.0-beta1
4.2.0-RC1
4.2.0
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.3.0-RC1
4.3.0
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7
4.3.8
4.3.9
4.3.10
4.3.11
4.4.0-beta1
4.4.0-RC1
4.4.0-RC2
4.4.0
4.4.1
4.4.2
4.4.3
4.4.4
4.4.5
4.4.6
4.4.7
4.4.8
4.4.9
4.4.10
4.4.11
4.4.12
4.4.13
4.4.14
4.4.15
4.4.16
4.4.17
4.4.18
4.4.19
4.4.20
4.4.21
4.4.22
4.4.23
4.4.24
4.4.25
4.4.26
4.4.27
4.4.28
4.4.29
4.4.30
4.4.31
4.4.32
4.4.33
4.4.34
4.4.35
4.4.36
4.4.37
4.4.38
4.4.39
4.4.40
4.4.41
4.4.42
4.4.43
4.4.44
4.4.45
4.4.46
4.4.47
4.4.48
4.4.49
4.4.50
4.4.51
4.4.52
4.4.53
4.4.54
4.4.55
4.4.56
4.4.57
4.5.0-beta1
4.5.0-beta2
4.5.0-beta3
4.5.0-RC1
4.5.0-RC2
4.5.0
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
4.5.8
4.5.9
4.5.10
4.5.11
4.5.12
4.5.13
4.5.14
4.6.0-RC1
4.6.0-RC2
4.6.0-RC3
4.6.0
4.6.1
4.6.2
4.6.3
4.6.4
4.6.5
4.6.6
4.6.7
4.6.8
4.6.9
4.6.10
4.6.11
4.6.12
4.6.13
4.6.14
4.7.0-RC1
4.7.0-RC2
4.7.0-RC3
4.7.0-RC4
4.7.0
4.7.1
4.7.2
4.7.3
4.7.4
4.7.5
4.7.6
4.7.7
4.8.0-RC1
4.8.0-RC2
4.8.0
4.8.1
4.8.2
4.8.3
4.8.4
4.8.5
4.8.6
4.8.7
4.8.8
4.9.0-RC1
4.9.0-RC2
4.9.0
4.9.1
4.9.2
4.9.3
4.9.4
4.9.5
4.9.6
4.9.7
4.9.8
4.9.9
4.9.10
4.9.11
4.9.12
4.9.13
4.9.14
4.9.15
4.9.16
4.9.17
4.9.18
4.9.19
4.9.20
4.9.21
4.9.22
4.9.23
4.9.24
4.9.25
4.9.26
4.9.27
4.9.28
4.9.29
4.9.30
4.9.31
4.9.32
4.9.33
4.9.34
4.9.35
4.9.36
4.9.37
4.9.38
4.9.39
4.9.40
4.9.41
4.9.42
4.10.0-RC1
4.10.0-RC2
4.10.0-RC3
4.10.0-RC4
4.10.0
4.10.1
4.10.2
4.10.3
4.10.4
4.10.5
4.10.6
4.10.7
4.11.0-RC1
4.11.0-RC2
4.11.0
4.11.1
4.11.2
4.11.3
4.11.4
4.11.5
4.11.6
4.11.7
4.11.8
4.11.9
4.12.0-RC1
4.12.0-RC2
4.12.0-RC3
4.12.0
4.12.1
4.12.2
4.12.3
4.12.4
4.12.5
4.12.6
4.12.7
4.13.0-RC1
4.13.0-RC2
4.13.0-RC3
4.13.0
4.13.1
4.13.2
4.13.3
4.13.4
4.13.5
4.13.6
4.13.7
4.13.8
4.13.9
4.13.10
4.13.11
4.13.12
4.13.13
4.13.14
4.13.15
4.13.16
4.13.17
4.13.18
4.13.19
4.13.20
4.13.21
4.13.22
4.13.23
4.13.24
4.13.25
4.13.26
4.13.27
4.13.28
4.13.29
4.13.30
4.13.31
4.13.32
4.13.33
4.13.34
4.13.35
4.13.36
4.13.37
4.13.38
4.13.39
4.13.40
4.13.41
4.13.42
4.13.43
4.13.44
4.13.45
4.13.46
4.13.47
4.13.48
4.13.49
4.13.50
4.13.51
4.13.52
4.13.53
4.13.54
4.13.55
4.13.56
4.13.57
4.13.58
5.*
5.0.0-RC1
5.0.0-RC2
5.0.0-RC3
5.0.0-RC4
5.0.0
5.0.1
5.0.2
5.0.3
5.0.4
5.0.5
5.0.6
5.0.7
5.0.8
5.0.9
5.0.10
5.1.0-RC1
5.1.0-RC2
5.1.0-RC3
5.1.0
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
5.1.8
5.1.9
5.1.10
5.1.11
5.2.0-RC1
5.2.0-RC2
5.2.0-RC3
5.2.0-RC4
5.2.0-RC5
5.2.0-RC6
5.2.0
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.2.8
5.2.9
5.2.10
5.3.0-RC1
5.3.0-RC2
5.3.0-RC3
5.3.0-RC4
5.3.0
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.3.7
5.3.8
5.3.9
5.3.10
5.3.11
5.3.12
5.3.13
5.3.14
5.3.15
5.3.16
5.3.17
5.3.18
5.3.19
5.3.20
5.3.21
5.3.22
5.3.23
5.3.24
5.3.25
5.3.26
5.3.27
5.3.28
5.3.29
5.3.30
5.3.31
5.3.32
5.3.33
5.3.34
5.3.35
5.3.36
5.3.37
5.3.38
5.3.39
5.3.40
5.3.41
5.3.42
5.3.43
5.3.44
5.3.45
5.3.46
5.3.47
5.3.48
5.3.49

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-mfxh-vp55-7gc6/GHSA-mfxh-vp55-7gc6.json"

Packagist / contao/core-bundle

Package

Name
contao/core-bundle
Purl
pkg:composer/contao/core-bundle

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.4.0-RC1
Fixed
5.7.12

Affected versions

5.*
5.4.0-RC1
5.4.0-RC2
5.4.0-RC3
5.4.0-RC4
5.4.0
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.4.8
5.4.9
5.4.10
5.4.11
5.4.12
5.4.13
5.4.14
5.5.0-RC1
5.5.0-RC2
5.5.0-RC3
5.5.0-RC4
5.5.0
5.5.1
5.5.2
5.5.3
5.5.4
5.5.5
5.5.6
5.5.7
5.5.8
5.5.9
5.5.10
5.5.11
5.5.12
5.5.13
5.5.14
5.5.15
5.5.16
5.6.0-RC1
5.6.0-RC2
5.6.0-RC3
5.6.0
5.6.1
5.6.2
5.6.3
5.6.4
5.6.5
5.6.6
5.6.7
5.6.8
5.6.9
5.6.10
5.6.11
5.7.0-RC1
5.7.0-RC2
5.7.0-RC3
5.7.0-RC4
5.7.0
5.7.1
5.7.2
5.7.3
5.7.4
5.7.5
5.7.6
5.7.7
5.7.8
5.7.9
5.7.10
5.7.11

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-mfxh-vp55-7gc6/GHSA-mfxh-vp55-7gc6.json"