CVE-2026-42245 (GCVE-0-2026-42245)

Vulnerability from cvelistv5 – Published: 2026-05-09 19:37 – Updated: 2026-05-12 18:30
VLAI
Title
net-imap: Quadratic complexity when reading response literals
Summary
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Severity
2.3 (Low)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-12 17:53 UTC
CWE
  • CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
Impacted products
Vendor Product Version CPE status
ruby net-imap Affected: < 0.4.24
Affected: >= 0.5.0, < 0.5.14
Affected: >= 0.6.0, < 0.6.4
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-42245",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-12T17:53:55.917796Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-12T18:30:58.415Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "net-imap",
          "vendor": "ruby",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.4.24"
            },
            {
              "status": "affected",
              "version": "\u003e= 0.5.0, \u003c 0.5.14"
            },
            {
              "status": "affected",
              "version": "\u003e= 0.6.0, \u003c 0.6.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client\u0027s CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 2.3,
            "baseSeverity": "LOW",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-407",
              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-09T19:37:08.905Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw"
        },
        {
          "name": "https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96"
        },
        {
          "name": "https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda"
        },
        {
          "name": "https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819"
        },
        {
          "name": "https://github.com/ruby/net-imap/releases/tag/v0.4.24",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/releases/tag/v0.4.24"
        },
        {
          "name": "https://github.com/ruby/net-imap/releases/tag/v0.5.14",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/releases/tag/v0.5.14"
        },
        {
          "name": "https://github.com/ruby/net-imap/releases/tag/v0.6.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ruby/net-imap/releases/tag/v0.6.4"
        }
      ],
      "source": {
        "advisory": "GHSA-q2mw-fvj9-vvcw",
        "discovery": "UNKNOWN"
      },
      "title": "net-imap: Quadratic complexity when reading response literals"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-42245",
    "datePublished": "2026-05-09T19:37:08.905Z",
    "dateReserved": "2026-04-25T05:37:12.118Z",
    "dateUpdated": "2026-05-12T18:30:58.415Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-42245",
      "date": "2026-08-18",
      "epss": "0.0041",
      "percentile": "0.34138"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-42245\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-09T20:16:28.017\",\"lastModified\":\"2026-07-24T19:10:00.160\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client\u0027s CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.\"},{\"lang\":\"es\",\"value\":\"Net::IMAP implementa la funcionalidad de cliente del Protocolo de Acceso a Mensajes de Internet (IMAP) en Ruby. Antes de las versiones 0.4.24, 0.5.14 y 0.6.4, Net::IMAP::ResponseReader tiene una complejidad temporal cuadr\u00e1tica al leer respuestas grandes que contienen muchos literales de cadena. Un servidor hostil puede enviar respuestas dise\u00f1adas para agotar la CPU del cliente para un ataque de denegaci\u00f3n de servicio. Este problema ha sido parcheado en las versiones 0.4.24, 0.5.14 y 0.6.4.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"ruby\",\"product\":\"net-imap\",\"versions\":[{\"version\":\"\u003c 0.4.24\",\"status\":\"affected\"},{\"version\":\"\u003e= 0.5.0, \u003c 0.5.14\",\"status\":\"affected\"},{\"version\":\"\u003e= 0.6.0, \u003c 0.6.4\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":2.3,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"PASSIVE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"LOW\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-05-12T17:53:55.917796Z\",\"id\":\"CVE-2026-42245\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-407\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:ruby-lang:net\\\\:\\\\:imap:*:*:*:*:*:ruby:*:*\",\"versionEndExcluding\":\"0.4.24\",\"matchCriteriaId\":\"05DB8FF3-7546-470A-BBB4-4DCAEAD83D6F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:ruby-lang:net\\\\:\\\\:imap:*:*:*:*:*:ruby:*:*\",\"versionStartIncluding\":\"0.5.0\",\"versionEndExcluding\":\"0.5.14\",\"matchCriteriaId\":\"2CCEB891-1D8F-4431-A79C-2A7560A84F4E\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:ruby-lang:net\\\\:\\\\:imap:*:*:*:*:*:ruby:*:*\",\"versionStartIncluding\":\"0.6.0\",\"versionEndExcluding\":\"0.6.4\",\"matchCriteriaId\":\"9A6D1995-BFA3-490F-967D-252CA7BE2264\"}]}]}],\"references\":[{\"url\":\"https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/ruby/net-imap/releases/tag/v0.4.24\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/ruby/net-imap/releases/tag/v0.5.14\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/ruby/net-imap/releases/tag/v0.6.4\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Mitigation\",\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-17T12:12:15+00:00",
      "cve": "CVE-2026-42245",
      "id": "CVE-2026-42245",
      "initial_release_date": "2026-05-09T19:37:08.905000+00:00",
      "product_status:fixed": "954",
      "product_status:known_not_affected": "9",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "ruby: net-imap: Net::IMAP: Denial of Service via crafted IMAP responses",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42245.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-42245\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-12T17:53:55.917796Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-12T17:54:00.543Z\"}}], \"cna\": {\"title\": \"net-imap: Quadratic complexity when reading response literals\", \"source\": {\"advisory\": \"GHSA-q2mw-fvj9-vvcw\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV4_0\": {\"version\": \"4.0\", \"baseScore\": 2.3, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N\", \"userInteraction\": \"PASSIVE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"LOW\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"ruby\", \"product\": \"net-imap\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.4.24\"}, {\"status\": \"affected\", \"version\": \"\u003e= 0.5.0, \u003c 0.5.14\"}, {\"status\": \"affected\", \"version\": \"\u003e= 0.6.0, \u003c 0.6.4\"}]}], \"references\": [{\"url\": \"https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw\", \"name\": \"https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96\", \"name\": \"https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda\", \"name\": \"https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819\", \"name\": \"https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ruby/net-imap/releases/tag/v0.4.24\", \"name\": \"https://github.com/ruby/net-imap/releases/tag/v0.4.24\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ruby/net-imap/releases/tag/v0.5.14\", \"name\": \"https://github.com/ruby/net-imap/releases/tag/v0.5.14\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ruby/net-imap/releases/tag/v0.6.4\", \"name\": \"https://github.com/ruby/net-imap/releases/tag/v0.6.4\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client\u0027s CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-407\", \"description\": \"CWE-407: Inefficient Algorithmic Complexity\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-05-09T19:37:08.905Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-42245\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-12T18:30:58.415Z\", \"dateReserved\": \"2026-04-25T05:37:12.118Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-05-09T19:37:08.905Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.