CVE-2026-107848 — Contao: Cross-site request forgery in custom backend actions
Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, RequestTokenListener validates REQUEST_TOKEN only for POST requests, while the declarative GET guard runs only when an act parameter is present. Backend actions dispatched through the key parameter can therefore execute without a CSRF token when an authenticated backend user loads an attacker-controlled URL. Reachable actions remain limited to modules available to that user, and the advisory demonstrates destructive or state-changing actions rather than privilege escalation. This issue is fixed in versions 5.3.50 and 5.7.12.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.1% (30-day exploitation probability)+0
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Composer Contao/core-bundle: fixed in version 5.3.50 — github.com (GitHub Security Advisories)
- Composer Contao/core-bundle: fixed in version 5.7.12 — github.com (GitHub Security Advisories)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Contao Contao, Composer Contao/core-bundle).
- Apply the fixed version or the patch documented under Remediation.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- Search available logs for exploit probes matching the vulnerability class (csrf), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Contao | Contao | version >= 4.0.0, < 5.3.50version >= 5.4.0-RC1, < 5.7.12 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Composer | Contao/core-bundle | ≥ 4.0.0 and < 5.3.50≥ 5.4.0-RC1 and < 5.7.12 | Vulnerable | GitHub Security Advisories |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 3.5 | CVSS 3.1 | Low | 2.1 | 1.4 | security-advisories@github.com via NIST National Vulnerability Database |
| 3.5 | CVSS 3.1 | Low | — | — | GitHub, Inc. via GitHub Security Advisories |
| 3.5 | CVSS 3.1 | Low | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.11%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · contao/contao
- SSVC assessment updated
- Fix documented
- Affected products added · composer/contao/core-bundle
- Record published
- CVSS changed · 3.5
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 13, 2026 – Oct 13, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
4 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-107851 Contao: Improper access control in the table access voter 6d
- Medium CVE-2026-107850 Contao: Improper access control in the preview links module 6d
- Medium CVE-2026-107843 Contao: The registration module re-sends activation mails on any unauthenticated POST, with no throttle and no captcha check 6d
- Medium CVE-2026-107842 Contao: Protected page content is disclosed to anonymous visitors after contao.search.index_protected is disabled 6d
- Medium CVE-2026-107844 Contao: Path traversal in the images controller 6d
- Critical CVE-2026-107845 Contao: Cross-site scripting in the comments bundle 6d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-107848 is "Contao: Cross-site request forgery in custom backend actions", rated Low. It affects Contao (Contao); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.5 describes technical severity. EPSS 0.11% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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