In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, an attacker controlling the unpacking format (similar to format string vulnerabilities) can trigger a buffer under-read in the String#unpack method, resulting in a massive and controlled information disclosure.
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ruby | Ruby-lang | 2.2.0 (including) | 2.2.10 (excluding) |
| Ruby | Ruby-lang | 2.3.0 (including) | 2.3.7 (excluding) |
| Ruby | Ruby-lang | 2.4.0 (including) | 2.4.4 (excluding) |
| Ruby | Ruby-lang | 2.5.0 (including) | 2.5.1 (excluding) |
| Ruby | Ruby-lang | 2.6.0-preview1 (including) | 2.6.0-preview1 (including) |
| Red Hat Enterprise Linux 7 | RedHat | ruby-0:2.0.0.648-36.el7 | * |
| Red Hat Enterprise Linux 7.4 Advanced Update Support | RedHat | ruby-0:2.0.0.648-36.el7_4 | * |
| Red Hat Enterprise Linux 7.4 Telco Extended Update Support | RedHat | ruby-0:2.0.0.648-36.el7_4 | * |
| Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions | RedHat | ruby-0:2.0.0.648-36.el7_4 | * |
| Red Hat Enterprise Linux 7.5 Extended Update Support | RedHat | ruby-0:2.0.0.648-36.el7_5 | * |
| Red Hat Enterprise Linux 7.6 Extended Update Support | RedHat | ruby-0:2.0.0.648-37.el7_6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | rh-ruby23-ruby-0:2.3.8-69.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | rh-ruby24-ruby-0:2.4.5-91.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby23-ruby-0:2.3.8-69.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby24-ruby-0:2.4.5-91.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby25-ruby-0:2.5.3-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby23-ruby-0:2.3.8-69.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby24-ruby-0:2.4.5-91.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby25-ruby-0:2.5.3-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | RedHat | rh-ruby23-ruby-0:2.3.8-69.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | RedHat | rh-ruby24-ruby-0:2.4.5-91.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | RedHat | rh-ruby25-ruby-0:2.5.3-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | RedHat | rh-ruby23-ruby-0:2.3.8-69.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | RedHat | rh-ruby24-ruby-0:2.4.5-91.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | RedHat | rh-ruby25-ruby-0:2.5.3-6.el7 | * |
| Ruby1.9.1 | Ubuntu | trusty | * |
| Ruby2.0 | Ubuntu | trusty | * |
| Ruby2.3 | Ubuntu | artful | * |
| Ruby2.3 | Ubuntu | xenial | * |
| Ruby2.5 | Ubuntu | bionic | * |
| Ruby2.5 | Ubuntu | devel | * |
When an attacker can modify an externally-controlled format string, this can lead to buffer overflows, denial of service, or data representation problems. It should be noted that in some circumstances, such as internationalization, the set of format strings is externally controlled by design. If the source of these format strings is trusted (e.g. only contained in library files that are only modifiable by the system administrator), then the external control might not itself pose a vulnerability.