CVE-2025-61911

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

Summary

The sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured.

Details

The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 happily computes without performing adequate logic to ensure a fully escaped return value.

PoC

>>> import ldap.filter

Exploitable

>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=1)
'abc@*()/xyz'
>>> ldap.filter.escape_filter_chars({"abc@*()/xyz": 1}, escape_mode=1)
'abc@*()/xyz'

Not exploitable

>>> ldap.filter.escape_filter_chars("abc@*()/xyz", escape_mode=1)
'abc@\\2a\\28\\29\\2fxyz'
>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib64/python3.12/site-packages/ldap/filter.py", line 41, in escape_filter_chars
    s = assertion_value.replace('\\', r'\5c')
        ^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'list' object has no attribute 'replace'
>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib64/python3.12/site-packages/ldap/filter.py", line 36, in escape_filter_chars
    r.append("\\%02x" % ord(c))
                        ^^^^^^
TypeError: ord() expected a character, but string of length 11 found

Impact

If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them.

With Python being a dynamically typed language, and the commonly used JSON format supporting list and dict, it is to be expected that Python applications may commonly forward unchecked and potentially malicious list and dict objects to the vulnerable sanitization method.

The vulnerable escape_mode=1 configuration does not appear to be widely used.

Suggested Fix

Add a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. Any application that uses this helper to construct DNs from untrusted input can be made to consistently fail before a request is sent to the LDAP server (e.g., AD), resulting in a client-side denial of service. Version 3.4.5 contains a patch for the issue.(CVE-2025-61912)

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. Any application that uses this helper to construct DNs from untrusted input can be made to consistently fail before a request is sent to the LDAP server (e.g., AD), resulting in a client-side denial of service. Version 3.4.5 contains a patch for the issue.(CVE-2025-61912)

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. Any application that uses this helper to construct DNs from untrusted input can be made to consistently fail before a request is sent to the LDAP server (e.g., AD), resulting in a client-side denial of service. Version 3.4.5 contains a patch for the issue.(CVE-2025-61912)

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. Any application that uses this helper to construct DNs from untrusted input can be made to consistently fail before a request is sent to the LDAP server (e.g., AD), resulting in a client-side denial of service. Version 3.4.5 contains a patch for the issue.(CVE-2025-61912)

python-ldap: python-ldap provides an object-oriented API to access LDAP directory servers from Python programs. Mainly it wraps the OpenLDAP 2.x libs for that purpose. Additionally the package contains modules for other LDAP-related stuff (e.g. processing LDIF, LDAPURLs, LDAPv3 schema, LDAPv3 extended operations and controls, etc.).

Security Fix(es):

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.(CVE-2025-61911)

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, ldap.dn.escape_dn_chars() escapes \x00 incorrectly by emitting a backslash followed by a literal NUL byte instead of the RFC-4514 hex form \00. Any application that uses this helper to construct DNs from untrusted input can be made to consistently fail before a request is sent to the LDAP server (e.g., AD), resulting in a client-side denial of service. Version 3.4.5 contains a patch for the issue.(CVE-2025-61912)

Summary

The sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured.

Details

The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 happily computes without performing adequate logic to ensure a fully escaped return value.

PoC

>>> import ldap.filter

Exploitable

>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=1)
'abc@*()/xyz'
>>> ldap.filter.escape_filter_chars({"abc@*()/xyz": 1}, escape_mode=1)
'abc@*()/xyz'

Not exploitable

>>> ldap.filter.escape_filter_chars("abc@*()/xyz", escape_mode=1)
'abc@\\2a\\28\\29\\2fxyz'
>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib64/python3.12/site-packages/ldap/filter.py", line 41, in escape_filter_chars
    s = assertion_value.replace('\\', r'\5c')
        ^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'list' object has no attribute 'replace'
>>> ldap.filter.escape_filter_chars(["abc@*()/xyz"], escape_mode=2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib64/python3.12/site-packages/ldap/filter.py", line 36, in escape_filter_chars
    r.append("\\%02x" % ord(c))
                        ^^^^^^
TypeError: ord() expected a character, but string of length 11 found

Impact

If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them.

With Python being a dynamically typed language, and the commonly used JSON format supporting list and dict, it is to be expected that Python applications may commonly forward unchecked and potentially malicious list and dict objects to the vulnerable sanitization method.

The vulnerable escape_mode=1 configuration does not appear to be widely used.

Suggested Fix

Add a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

python-ldap is a lightweight directory access protocol (LDAP) client API for Python. In versions prior to 3.4.5, the sanitization method ldap.filter.escape_filter_chars can be tricked to skip escaping of special characters when a crafted list or dict is supplied as the assertion_value parameter, and the non-default escape_mode=1 is configured. The method ldap.filter.escape_filter_chars supports 3 different escaping modes. escape_mode=0 (default) and escape_mode=2 happen to raise exceptions when a list or dict object is supplied as the assertion_value parameter. However, escape_mode=1 computes without performing adequate logic to ensure a fully escaped return value. If an application relies on the vulnerable method in the python-ldap library to escape untrusted user input, an attacker might be able to abuse the vulnerability to launch ldap injection attacks which could potentially disclose or manipulate ldap data meant to be inaccessible to them. Version 3.4.5 fixes the issue by adding a type check at the start of the ldap.filter.escape_filter_chars method to raise an exception when the supplied assertion_value parameter is not of type str.

These are all security issues fixed in the python311-ldap-3.4.5-1.1 package on the GA media of openSUSE Tumbleweed.

This update for python-ldap fixes the following issues:

• CVE-2025-61911: Enforce str for escape_filter_chars (bsc#1251912).
• CVE-2025-61912: Escape NULs as per RFC 4514 in escape_dn_chars (bsc#1251913).

This update for python-ldap fixes the following issues:

• CVE-2025-61911: Enforce str for escape_filter_chars (bsc#1251912).
• CVE-2025-61912: Escape NULs as per RFC 4514 in escape_dn_chars (bsc#1251913).

This update for python-ldap fixes the following issues:

• CVE-2025-61911: Enforce str for escape_filter_chars (bsc#1251912).
• CVE-2025-61912: Escape NULs as per RFC 4514 in escape_dn_chars (bsc#1251913).

This update for python-ldap fixes the following issues:

• CVE-2025-61911: Enforce str for escape_filter_chars (bsc#1251912).
• CVE-2025-61912: Escape NULs as per RFC 4514 in escape_dn_chars (bsc#1251913).

It was discovered that Python LDAP incorrectly handled special characters in the special character filtering function. A remote attacker could possibly use this issue to perform LDAP injection attacks. (CVE-2025-61911)

Arad Inbar discovered that Python LDAP incorrectly escaped NUL character bytes. An attacker could possibly use this issue to cause a denial of service. (CVE-2025-61912)