Summary
Contao: Possible path traversal in job download URIs
An authenticated backend user who can access one job can request an attachment identifier containing ../ segments and make the job attachment download endpoint read a file from another job directory inside var/job-attachments.
The controller authorizes only the jobUuid route parameter. The later attachment lookup joins that authorized job UUID with the attacker-controlled identifier, then passes the combined path to the virtual filesystem. VirtualFilesystem::resolve() canonicalizes the whole path and only rejects paths that escape the filesystem mount, so authorized-job/../victim-job/debug_log.csv becomes victim-job/debug_log.csv.
This is a cross-job authorization bypass for known job attachment paths. It is not a practical brute-force against unknown jobs because job directories are UUID v4 values.
Root Cause
JobsController::downloadJobAttachment() checks access to the route jobUuid before loading the attachment:
$job = $this->jobs->getByUuid($jobUuid);
if (!$job || !$this->jobs->hasAccess($job)) {
throw $this->createNotFoundException();
}
$attachment = $this->jobs->getAttachment($jobUuid, $identifier);
Jobs::getAttachment() then resolves a path built from the authorized job UUID and the attacker-controlled identifier:
$fileItem = $this->jobAttachmentsStorage->get($this->getAttachmentIdentifier($job, $identifier));
return $job->getUuid().'/'.$identifier;
VirtualFilesystem::resolve() canonicalizes the combined path. It rejects absolute paths and paths that start with .., but it does not preserve the authorized job directory as a boundary:
$path = Path::canonicalize($location);
if (str_starts_with($path, '..')) {
throw new \OutOfBoundsException(...);
}
return Path::join($this->prefix, $path);
Therefore:
<authorized-job>/../<victim-job>/debug_log.csv
canonicalizes to:
<victim-job>/debug_log.csv
which remains inside the job-attachments filesystem mount and is accepted.
Impact
A low-privileged backend user can read another job's attachment if they know or obtain the target job UUID and attachment filename. Built-in crawler jobs attach CSV logs such as debug_log.csv, broken-link-checker_log.csv, and search-index_log.csv, which can contain crawled URLs, referring URLs, tags, and error messages.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-55825 has a CVSS score of 3.1 (Low). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.7.7); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Treat the attachment identifier as a filename, not a path:
- Reject
/,\, NUL, and dot-segment components inidentifier. - Add a route requirement that prevents slashes in
{identifier}if nested attachment paths are not intended. - After resolving, assert the canonical relative path starts with
<authorized-job-uuid>/before returning aFilesystemItem. - Apply the same identifier validation in
Jobs::addAttachment()so future producers/extensions cannot write outside the owning job directory.
Frequently Asked Questions
- What is CVE-2026-55825? CVE-2026-55825 is a low-severity path traversal vulnerability in contao/contao (composer), affecting versions >= 5.7.0, < 5.7.7. It is fixed in 5.7.7. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-55825? CVE-2026-55825 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-55825?
contao/contao(composer) (versions >= 5.7.0, < 5.7.7)contao/core-bundle(composer) (versions >= 5.7.0, < 5.7.7)
- Is there a fix for CVE-2026-55825? Yes. CVE-2026-55825 is fixed in 5.7.7. Upgrade to this version or later.
- Is CVE-2026-55825 exploitable, and should I be worried? Whether CVE-2026-55825 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55825 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55825?
- Upgrade
contao/contaoto 5.7.7 or later - Upgrade
contao/core-bundleto 5.7.7 or later
- Upgrade