The Debian backport of the fix for CVE-2017-3137 leads to assertion failure in validator.c:1858; Affects Debian versions 9.9.5.dfsg-9+deb8u15; 9.9.5.dfsg-9+deb8u18; 9.10.3.dfsg.P4-12.3+deb9u5; 9.11.5.P4+dfsg-5.1 No ISC releases are affected. Other packages from other distributions who did similar backports for the fix for 2017-3137 may also be affected.
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Debian_linux | Debian | 8.0 (including) | 8.0 (including) |
| Debian_linux | Debian | 9.0 (including) | 9.0 (including) |
| Debian_linux | Debian | 10.0 (including) | 10.0 (including) |
| Bind9 | Ubuntu | upstream | * |
While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.