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Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process. An issue was discovered in the resolv gem before 0.7.2 for Ruby. Resolv::DNS::MessageEncoder wrote a DNS label's length into a single octet without checking its range. A label longer than 255 octets had its length stored modulo 256 but the label data was written unchanged, and thus the bytes on the wire described a different name than the one the application asked to encode. RFC 1035 section 2.3.4 limits a label to 63 octets, and the two high bits of the length octet are reserved for compression pointers. put_string packed the length with put_pack("C", d.length) and put_label used it for labels, and thus any value from 0 to 255 could end up as a label length octet, including the reserved 0x40-0xBF range and the 0xC0-0xFF pointer range. Resolv::DNS::Name.create did not check per-label or total name length either, and thus an attacker-controlled hostname reached the encoder unchanged. An application that resolves an attacker-controlled hostname sends a query whose wire bytes name a domain the attacker chose. A hostname suffix that the application validates against an allowlist becomes padding that never appears on the wire, and thus allowlist and egress checks can be bypassed. The recursive resolver caches the response under the attacker's name, and DNS logs record that name rather than the one the application asked for. A label length whose low octet lands in the 0xC0-0xFF range produces a length octet that conforming parsers read as the start of a compression pointer, with the following attacker-controlled byte as the offset.
FEDORA-2026-fbf03424ec (ruby-4.0.6-38.fc46) has been submitted as an update to Fedora 46. https://bodhi.fedoraproject.org/updates/FEDORA-2026-fbf03424ec
FEDORA-2026-ab0c751524 (ruby-4.0.6-38.fc45) has been submitted as an update to Fedora 45. https://bodhi.fedoraproject.org/updates/FEDORA-2026-ab0c751524
FEDORA-2026-da06bdeb38 (ruby-4.0.6-38.fc44) has been submitted as an update to Fedora 44. https://bodhi.fedoraproject.org/updates/FEDORA-2026-da06bdeb38
FEDORA-2026-b3bccd6a30 (ruby-3.4.10-32.fc43) has been submitted as an update to Fedora 43. https://bodhi.fedoraproject.org/updates/FEDORA-2026-b3bccd6a30
FEDORA-2026-fbf03424ec (ruby-4.0.6-38.fc46) has been pushed to the Fedora 46 stable repository. If problem still persists, please make note of it in this bug report.
FEDORA-2026-ab0c751524 has been pushed to the Fedora 45 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-ab0c751524` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-ab0c751524 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2026-b3bccd6a30 has been pushed to the Fedora 43 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b3bccd6a30` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b3bccd6a30 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2026-da06bdeb38 has been pushed to the Fedora 44 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-da06bdeb38` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-da06bdeb38 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2026-ab0c751524 (ruby-4.0.6-38.fc45) has been pushed to the Fedora 45 stable repository. If problem still persists, please make note of it in this bug report.
FEDORA-2026-da06bdeb38 (ruby-4.0.6-38.fc44) has been pushed to the Fedora 44 stable repository. If problem still persists, please make note of it in this bug report.
FEDORA-2026-b3bccd6a30 (ruby-3.4.10-32.fc43) has been pushed to the Fedora 43 stable repository. If problem still persists, please make note of it in this bug report.