Summary
EGroupware Vulnerable to Local File Inclusion via file:// URI in Mail Compose
Full technical description
The function processes image URLs embedded in an HTML email body without validating or restricting URI schemes. The check !str_starts_with($myUrl, 'http') evaluates to true for file:// URIs, causing file_get_contents($basedir . urldecode($myUrl)) to read arbitrary files from the server filesystem and embed them as inline MIME attachments in outgoing email.
str_starts_with('file:///etc/passwd', 'http') → false
!false → true
// api/src/Mail.php
foreach($images[2] as $i => $url)
{
//$isData = false;
$basedir = $data = '';
$needTempFile = true;
$attachmentData = ['name' => '', 'type' => '', 'file' => '', 'tmp_name' => ''];
try
{
// do not change urls for absolute images (thanks to corvuscorax)
if (!str_starts_with($url, 'data:'))
{
$attachmentData['name'] = basename($url); // need to resolve all sort of url
if (($directory = dirname($url)) == '.') $directory = '';
$ext = pathinfo($attachmentData['name'], PATHINFO_EXTENSION);
$attachmentData['type'] = MimeMagic::ext2mime($ext);
if ( strlen($directory) > 1 && !str_ends_with($directory, '/')) { $directory .= '/'; }
..
...
....
// processURL2InlineImages function
if ( $myUrl[0]!='/' && strlen($basedir) > 1 && !str_ends_with($basedir, '/')) { $basedir .= '/'; }
if ($needTempFile && empty($attachment) && !str_starts_with($myUrl, "http"))
{
try {
$data = file_get_contents($basedir.urldecode($myUrl));
}
catch (\Throwable $e) {
_egw_log_exception($e);
}
}
}
if (str_starts_with($url, 'data:'))
PoC
- Log in as any authenticated EGroupware user with mail access and open the mail compose window.
- Switch to HTML body mode and insert:
<img src="file:///etc/passwd">. - The server executes file_get_contents('file:///etc/passwd'), writes the content to a temp file, and attaches it as an inline MIME part.
Impact
An authenticated attacker can read arbitrary files accessible by the web server process, including /etc/passwd, application configuration files containing database credentials, private TLS keys, and environment files.
CVE-2026-45016 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (26.5.20260507, 23.1.20260601); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Enforce a strict URI scheme allowlist before calling file_get_contents(). Replace the check !str_starts_with($myUrl, 'http') with if (!preg_match('#^https?://#i', $myUrl)) { continue; } to reject file://, ftp://, php://, data://, and any other non-HTTP scheme.
Frequently Asked Questions
- What is CVE-2026-45016? CVE-2026-45016 is a medium-severity security vulnerability in egroupware/egroupware (composer), affecting versions >= 26.0.20251208, < 26.5.20260507. It is fixed in 26.5.20260507, 23.1.20260601.
- How severe is CVE-2026-45016? CVE-2026-45016 has a CVSS score of 6.5 (Medium). 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 versions of egroupware/egroupware are affected by CVE-2026-45016? egroupware/egroupware (composer) versions >= 26.0.20251208, < 26.5.20260507 is affected.
- Is there a fix for CVE-2026-45016? Yes. CVE-2026-45016 is fixed in 26.5.20260507, 23.1.20260601. Upgrade to this version or later.
- Is CVE-2026-45016 exploitable, and should I be worried? Whether CVE-2026-45016 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-2026-45016 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-2026-45016?
- Upgrade
egroupware/egroupwareto 26.5.20260507 or later - Upgrade
egroupware/egroupwareto 23.1.20260601 or later
- Upgrade