Contao is an Open Source CMS. From version 4.1.0 until 5.3.50 and 5.7.12, ModuleRegistration::compile() enters its follow-up registration branch on any POST to a page containing the registration module without verifying FORM_SUBMIT or the preceding captcha result. resendActivationMail() can then invoke OptInToken::send() without rate limiting, allowing an unauthenticated attacker to cause repeated activation emails to be sent to an address with a pending registration and to determine whether that pending registration exists. The branch is reachable only when reg_activate is enabled and the target has an unconfirmed registration and opt-in token. This issue is fixed in versions 5.3.50 and 5.7.12.
CVE-2026-107843
MEDIUMPre-NVD 5.35.3
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 5.3Exploit: None knownExposed services: Not assessed
The CVE record names the fixed release — apply it.
- CVSS v3
- 5.3
- EG Score
- 5.3MEDIUMlow confidence
- EG Risk
- 28EG Risk 28/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity53% × 45%Exploitation0% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).Action: The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 9, 2026
Last Modified
October 9, 2026
Advisory Details (2)
Auto-updated Oct 9, 2026Fix named in the CVE record. Sources: github, github_commit.
github_commit
commit 2ea6117f9049 (contao/contao)
Fix landed in contao/contao commit 2ea6117f9049 — awaiting tagged release
https://github.com/contao/contao/commit/2ea6117f9049db7221679251cfc41e67d941a74bgithubMentions a patch (unverified)
Unrestricted activation email resending · Advisory · contao/contao · GitHub
https://github.com/contao/contao/security/advisories/GHSA-mfxh-vp55-7gc6Vendor Advisories for CVE-2026-107843(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-09 20:39 UTCEG score recompute
- 2026-10-09 19:34 UTCEG score recompute
- 2026-10-09 19:33 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-107843?
CVE-2026-107843 is a medium vulnerability published on October 9, 2026. Contao is an Open Source CMS. From version 4.1.0 until 5.3.50 and 5.7.12, ModuleRegistration::compile() enters its follow-up registration branch on any POST to a page containing the registration module without verifying FORMSUBMIT or the preceding captcha result. resendActivationMail() can then…
When was CVE-2026-107843 disclosed?
CVE-2026-107843 was first published on October 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-107843?
CVE-2026-107843 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-107843?
The CVE record for CVE-2026-107843 names the fix: "This issue is fixed in versions 5.3.50 and 5.7.12." The vendor advisories EchelonGraph has for CVE-2026-107843 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-107843
Is Your Infrastructure Affected by CVE-2026-107843?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.