Description
Buffer overflow in the extract_openvpn_cr function in openvpn-cr.c in openvpn-auth-ldap (aka the Three Rings Auth-LDAP plugin for OpenVPN) 2.0.4 allows attackers with a valid LDAP username and who can control the challenge/response password field to pass a string with more than 14 colons into this field and cause a buffer overflow.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openvpn-auth-ldap | 2.0.4-4 | — |
| Debian 13 | openvpn-auth-ldap | 2.0.4-4 | — |
| Debian 12 | openvpn-auth-ldap | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 26.04 LTS | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 25.10 | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 24.04 LTS | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 22.04 LTS | openvpn-auth-ldap | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 18.04 LTS | openvpn-auth-ldap | No fix yet | — |
| Ubuntu 16.04 LTS | openvpn-auth-ldap | No fix yet | — |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | openvpn-auth-ldap | 2.0.4-r7 | — |
| Alpine v3.23 | openvpn-auth-ldap | 2.0.4-r7 | — |
| Alpine v3.22 | openvpn-auth-ldap | 2.0.4-r7 | — |
| Alpine v3.21 | openvpn-auth-ldap | 2.0.4-r7 | — |