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Vulnerabilities

Vulnerability · CVE-2026-80212

An issue was discovered in the resolv gem before 0.7.2 for Ruby.

Published Aug 27, 2026 · catalog updated Oct 27, 2026 · An issue was discovered

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-80212. EPSS is 0.40%. Act only if a listed version of An issue was discovered is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (An issue was discovered).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.40%
Remediation
Advisory link
Affected products
Alpine:v3.21 ruby · Alpine:v3.22 ruby · Alpine:v3.23 ruby · Alpine:v3.24 ruby

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Alpine:v3.21 ruby0 → 3.3.13-r0
  • Alpine:v3.22 ruby0 → 3.4.12-r0
  • Alpine:v3.23 ruby0 → 3.4.12-r0
  • Alpine:v3.24 ruby0 → 3.4.12-r0

How to fix CVE-2026-80212

  • Upgrade

    CVE-2026-80212 lists a fix boundary at 3.3.13-r0. Compare the installed build with that boundary before you change production.

  • Version check

    Fixed in 3.3.13-r0 · 3 other ranges on the advisory

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-80212. EPSS is 0.40%. Act only if a listed version of An issue was discovered is installed.

Which versions are affected?

Compare what you have installed with 0 → 3.3.13-r0, 0 → 3.4.12-r0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.40%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 27, 2026 · Trivy Vulnerability DB

    Detected

    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 Resou

  2. Oct 27, 2026 · Trivy Vulnerability DB

    Fix available

    ruby fixed in 3.3.13-r0; ruby fixed in 3.4.12-r0; ruby fixed in 3.4.12-r0; ruby fixed in 3.4.12-r0

  3. Oct 27, 2026 · Trivy Vulnerability DB

    Fix available

    ruby fixed in 3.3.13-r0

  4. Oct 27, 2026 · Trivy Vulnerability DB

    Fix available

    ruby fixed in 3.4.12-r0

  5. Oct 27, 2026 · Trivy Vulnerability DB

    Updated

    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 Resou

Sources

  • CVE.orgVulnerability recordCVE-2026-80212

    Official CVE identifier

    cve.org
  • Trivy Vulnerability DBPackage advisoryALPINE-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 SvcPara

    osv.dev

References

Freshness

Last verified in this catalog Oct 27, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Trivy Vulnerability DBOct 28, 2026
  • CVE.orgOct 27, 2026