CVE-2021-3850

Workarounds

Ensure the parameters passed to ADOConnection::connect() or related functions (nConnect(), pConnect()) are not surrounded by single quotes.

Credits

Thanks to Emmet Leahy (@meme-lord) of Sorcery Ltd for reporting this vulnerability, and to the huntr team for their support.

References

• Original issue report https://huntr.dev/bounties/bdf5f216-4499-4225-a737-b28bc6f5801c/
• ADOdb reference issue #793

For more information

If you have any questions or comments about this advisory:

• Add a note in issue #793
• Contact the maintainers on Gitter

An attacker can inject values into a PostgreSQL connection string by providing a parameter surrounded by single quotes.

Depending on how the library is used in the client software, this may allow an attacker to bypass the login process, gain access to the server's IP address, etc.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2021-3850 has a CVSS score of 9.1 (Critical). The vector is network-reachable, no 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 (5.20.21, 5.21.4); upgrading removes the vulnerable code path.

Kodem intelligence

The vulnerability is fixed in ADOdb versions 5.20.21 (952de6c4273d9b1e91c2b838044f8c2111150c29) and 5.21.4 or later (b4d5ce70034c5aac3a1d51d317d93c037a0938d2).

The simplest patch is to delete line 29 in drivers/adodb-postgres64.inc.php:

diff --git a/drivers/adodb-postgres64.inc.php b/drivers/adodb-postgres64.inc.php
index d04b7f67..729d7141 100644
--- a/drivers/adodb-postgres64.inc.php
+++ b/drivers/adodb-postgres64.inc.php
@@ -26,7 +26,6 @@ function adodb_addslashes($s)
 {
    $len = strlen($s);
    if ($len == 0) return "''";
-   if (strncmp($s,"'",1) === 0 && substr($s,$len-1) == "'") return $s; // already quoted
 
    return "'".addslashes($s)."'";
 }

1. What is CVE-2021-3850? CVE-2021-3850 is a critical-severity improper authentication vulnerability in adodb/adodb-php (composer), affecting versions <= 5.20.20. It is fixed in 5.20.21, 5.21.4. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2021-3850? CVE-2021-3850 has a CVSS score of 9.1 (Critical). 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.
3. Which versions of adodb/adodb-php are affected by CVE-2021-3850? adodb/adodb-php (composer) versions <= 5.20.20 is affected.
4. Is there a fix for CVE-2021-3850? Yes. CVE-2021-3850 is fixed in 5.20.21, 5.21.4. Upgrade to this version or later.
5. Is CVE-2021-3850 exploitable, and should I be worried? Whether CVE-2021-3850 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
6. What actually determines whether CVE-2021-3850 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.
7. How do I fix CVE-2021-3850?
   • Upgrade adodb/adodb-php to 5.20.21 or later
   • Upgrade adodb/adodb-php to 5.21.4 or later