Fedora Account System
Red Hat Associate
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An issue was discovered in the resolv gem before 0.7.2 for Ruby. Resolv::DNS::Resource.get_class, Resolv::DNS::Resource::Generic.create, and Resolv::DNS::SvcParam::Generic.create generate a new class for each unknown DNS resource record (type, class) pair, or each unknown SvcParamKey, encountered while decoding a response. Each generated class was permanently registered both as a constant on Resource (or SvcParam::Generic) and as an entry in a class-lookup hash (ClassHash), and thus the class remained reachable through that constant after the response was discarded. Type and class are each 16-bit values, and thus an attacker controlling DNS responses (a spoofed response, or a malicious or hijacked upstream DNS server) has roughly 2^32 distinct (type, class) pairs to choose from. A single response of a few hundred kilobytes carrying tens of thousands of distinct unknown types permanently grows process memory by tens of megabytes; repeated responses accumulate without bound and are never reclaimed by garbage collection, because the constant keeps each class alive. Any code path that calls Resolv::DNS::Message.decode on attacker-influenced DNS responses is affected. resolv is a default gem, and thus this is reachable from a plain Ruby installation without any additional dependency.
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:72285 https://access.redhat.com/errata/RHSA-2026:72285
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:72286 https://access.redhat.com/errata/RHSA-2026:72286
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:72427 https://access.redhat.com/errata/RHSA-2026:72427
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:72484 https://access.redhat.com/errata/RHSA-2026:72484
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:72485 https://access.redhat.com/errata/RHSA-2026:72485
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:72785 https://access.redhat.com/errata/RHSA-2026:72785
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:73519 https://access.redhat.com/errata/RHSA-2026:73519
This issue has been addressed in the following products: Red Hat Enterprise Linux 10.0 Extended Update Support Via RHSA-2026:83570 https://access.redhat.com/errata/RHSA-2026:83570
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Via RHSA-2026:83572 https://access.redhat.com/errata/RHSA-2026:83572
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:83574 https://access.redhat.com/errata/RHSA-2026:83574
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.6 Extended Update Support Via RHSA-2026:83571 https://access.redhat.com/errata/RHSA-2026:83571
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Via RHSA-2026:86208 https://access.redhat.com/errata/RHSA-2026:86208
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.6 Extended Update Support Via RHSA-2026:86207 https://access.redhat.com/errata/RHSA-2026:86207
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Via RHSA-2026:95512 https://access.redhat.com/errata/RHSA-2026:95512
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Via RHSA-2026:95513 https://access.redhat.com/errata/RHSA-2026:95513
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat Enterprise Linux 8.8 Telecommunications Update Service Via RHSA-2026:95514 https://access.redhat.com/errata/RHSA-2026:95514
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Extended Lifecycle Support Via RHSA-2026:96099 https://access.redhat.com/errata/RHSA-2026:96099