# CVE-2026-80213: ruby3.4: Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-80213: 	An issue...

CVE-2026-80213 is fixed in 69 products on 1 platform, first by DEBIAN-CVE-2026-80213, released August 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-80213
- Priority: Routine
- CVSS: 4.0 (important)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 27, 2026

## Description

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-80213: 	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.  CVE-2026-80212: 	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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | ruby3.3 Debian 13.5 (trixie) | 3.3.13-0+deb13u1 | [DEBIAN-CVE-2026-80213](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80213.md) | Aug 27, 2026 |
| Linux | ruby3.4 amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-bundled-gems amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-bundled-gems-debuginfo amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-debuginfo amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-debugsource amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-default-gems amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-devel amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-doc amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-libs amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-libs-debuginfo amzn 2023 | 3.4.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-bigdecimal amzn 2023 | 3.1.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-bigdecimal-debuginfo amzn 2023 | 3.1.8-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-bundler amzn 2023 | 2.6.9-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-io-console amzn 2023 | 0.8.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-io-console-debuginfo amzn 2023 | 0.8.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-irb amzn 2023 | 1.14.3-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-json amzn 2023 | 2.9.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-json-debuginfo amzn 2023 | 2.9.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-minitest amzn 2023 | 5.25.4-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-power_assert amzn 2023 | 2.0.5-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-psych amzn 2023 | 5.2.2-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-psych-debuginfo amzn 2023 | 5.2.2-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-racc amzn 2023 | 1.8.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-racc-debuginfo amzn 2023 | 1.8.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rake amzn 2023 | 13.2.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rbs amzn 2023 | 3.8.0-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rbs-debuginfo amzn 2023 | 3.8.0-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rdoc amzn 2023 | 6.14.0-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rexml amzn 2023 | 3.4.4-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-rss amzn 2023 | 0.3.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-test-unit amzn 2023 | 3.6.7-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygem-typeprof amzn 2023 | 0.30.1-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygems amzn 2023 | 3.6.9-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby3.4-rubygems-devel amzn 2023 | 3.6.9-27.amzn2023.0.7 | [ALAS2023-2026-2145](https://patchblox.com/security/data/fix/linux/alas2023-2026-2145.md) | Sep 14, 2026 |
| Linux | ruby4.0 amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-bundled-gems amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-bundled-gems-debuginfo amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-debuginfo amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-debugsource amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-default-gems amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-devel amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-doc amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-libs amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-libs-debuginfo amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-bigdecimal amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-bigdecimal-debuginfo amzn 2023 | 4.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-bundler amzn 2023 | 4.0.3-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-io-console amzn 2023 | 0.8.2-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-io-console-debuginfo amzn 2023 | 0.8.2-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-irb amzn 2023 | 1.16.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-json amzn 2023 | 2.18.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-json-debuginfo amzn 2023 | 2.18.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-minitest amzn 2023 | 6.0.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-power_assert amzn 2023 | 3.0.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-psych amzn 2023 | 5.3.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-psych-debuginfo amzn 2023 | 5.3.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-racc amzn 2023 | 1.8.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-racc-debuginfo amzn 2023 | 1.8.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rake amzn 2023 | 13.3.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rbs amzn 2023 | 3.10.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rbs-debuginfo amzn 2023 | 3.10.0-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rdoc amzn 2023 | 7.0.3-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rexml amzn 2023 | 3.4.4-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-rss amzn 2023 | 0.3.2-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-test-unit amzn 2023 | 3.7.5-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygem-typeprof amzn 2023 | 0.31.1-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygems amzn 2023 | 4.0.3-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |
| Linux | ruby4.0-rubygems-devel amzn 2023 | 4.0.3-32.amzn2023.0.4 | [ALAS2023-2026-2144](https://patchblox.com/security/data/fix/linux/alas2023-2026-2144.md) | Sep 14, 2026 |

---

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