GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-56859 (GCVE-0-2026-56859)

Vulnerability from cvelistv5 – Published: 2026-08-13 21:58 – Updated: 2026-08-14 15:21
VLAI
Title
Add recursion depth guard during decode in encoding/xml
Summary
Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-14 15:21 UTC
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
Impacted products
Vendor Product Version CPE status
Go standard library encoding/xml Affected: 0 , < 1.25.13 (semver)
Affected: 1.26.0-0 , < 1.26.6 (semver)
Affected: 1.27.0-0 , < 1.27.0-rc.3 (semver)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-56859",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-14T15:21:09.615961Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-770",
                "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-14T15:21:46.218Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "encoding/xml",
          "product": "encoding/xml",
          "programRoutines": [
            {
              "name": "Decoder.push"
            },
            {
              "name": "Decoder.pop"
            },
            {
              "name": "Decoder.RawToken"
            },
            {
              "name": "Decoder.unmarshalPath"
            },
            {
              "name": "Decoder.unmarshal"
            },
            {
              "name": "Decoder.Decode"
            },
            {
              "name": "Decoder.DecodeElement"
            },
            {
              "name": "Decoder.Skip"
            },
            {
              "name": "Decoder.Token"
            },
            {
              "name": "Unmarshal"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.25.13",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.26.6",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.27.0-rc.3",
              "status": "affected",
              "version": "1.27.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-13T21:58:52.959Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/issue/80481"
        },
        {
          "url": "https://go.dev/cl/803320"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/94pEornpRlI"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-6088"
        }
      ],
      "title": "Add recursion depth guard during decode in encoding/xml"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-56859",
    "datePublished": "2026-08-13T21:58:52.959Z",
    "dateReserved": "2026-06-23T15:10:49.353Z",
    "dateUpdated": "2026-08-14T15:21:46.218Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-56859",
      "date": "2026-09-04",
      "epss": "0.00568",
      "percentile": "0.449"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-03T01:12:15.000Z",
      "cve": "CVE-2026-56859",
      "id": "msrc_CVE-2026-56859",
      "initial_release_date": "2026-08-20T22:01:58.000Z",
      "product_status:known_affected": "5",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Add recursion depth guard during decode in encoding/xml",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-56859.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-56859\",\"sourceIdentifier\":\"security@golang.org\",\"published\":\"2026-08-13T22:17:22.320\",\"lastModified\":\"2026-09-03T16:37:52.170\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion.\"}],\"affected\":[{\"source\":\"security@golang.org\",\"affectedData\":[{\"vendor\":\"Go standard library\",\"product\":\"encoding/xml\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://pkg.go.dev\",\"packageName\":\"encoding/xml\",\"programRoutines\":[{\"name\":\"Decoder.push\"},{\"name\":\"Decoder.pop\"},{\"name\":\"Decoder.RawToken\"},{\"name\":\"Decoder.unmarshalPath\"},{\"name\":\"Decoder.unmarshal\"},{\"name\":\"Decoder.Decode\"},{\"name\":\"Decoder.DecodeElement\"},{\"name\":\"Decoder.Skip\"},{\"name\":\"Decoder.Token\"},{\"name\":\"Unmarshal\"}],\"versions\":[{\"version\":\"0\",\"lessThan\":\"1.25.13\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"1.26.0-0\",\"lessThan\":\"1.26.6\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"1.27.0-0\",\"lessThan\":\"1.27.0-rc.3\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"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\":\"2026-08-14T15:21:09.615961Z\",\"id\":\"CVE-2026-56859\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-770\"}]}],\"references\":[{\"url\":\"https://go.dev/cl/803320\",\"source\":\"security@golang.org\"},{\"url\":\"https://go.dev/issue/80481\",\"source\":\"security@golang.org\"},{\"url\":\"https://groups.google.com/g/golang-announce/c/94pEornpRlI\",\"source\":\"security@golang.org\"},{\"url\":\"https://pkg.go.dev/vuln/GO-2026-6088\",\"source\":\"security@golang.org\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-04T14:38:16+00:00",
      "cve": "CVE-2026-56859",
      "id": "CVE-2026-56859",
      "initial_release_date": "2026-08-13T21:58:52.959000+00:00",
      "product_status:fixed": "638",
      "product_status:known_affected": "385",
      "product_status:known_not_affected": "52",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "encoding/xml: golang: Go: Denial of Service via XML decoding recursion depth issue",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56859.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-31T16:37:05Z",
      "cve": "CVE-2026-56859",
      "id": "CVE-2026-56859",
      "initial_release_date": "2026-08-14T23:48:56Z",
      "product_status:first_fixed": "12",
      "product_status:known_affected": "12",
      "product_status:known_not_affected": "143",
      "product_status:recommended": "283",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-56859",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-56859.json",
      "version": "6"
    },
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"shortName\": \"Go\", \"dateUpdated\": \"2026-08-13T21:58:52.959Z\"}, \"title\": \"Add recursion depth guard during decode in encoding/xml\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion.\"}], \"affected\": [{\"vendor\": \"Go standard library\", \"product\": \"encoding/xml\", \"collectionURL\": \"https://pkg.go.dev\", \"packageName\": \"encoding/xml\", \"versions\": [{\"version\": \"0\", \"lessThan\": \"1.25.13\", \"status\": \"affected\", \"versionType\": \"semver\"}, {\"version\": \"1.26.0-0\", \"lessThan\": \"1.26.6\", \"status\": \"affected\", \"versionType\": \"semver\"}, {\"version\": \"1.27.0-0\", \"lessThan\": \"1.27.0-rc.3\", \"status\": \"affected\", \"versionType\": \"semver\"}], \"programRoutines\": [{\"name\": \"Decoder.push\"}, {\"name\": \"Decoder.pop\"}, {\"name\": \"Decoder.RawToken\"}, {\"name\": \"Decoder.unmarshalPath\"}, {\"name\": \"Decoder.unmarshal\"}, {\"name\": \"Decoder.Decode\"}, {\"name\": \"Decoder.DecodeElement\"}, {\"name\": \"Decoder.Skip\"}, {\"name\": \"Decoder.Token\"}, {\"name\": \"Unmarshal\"}], \"defaultStatus\": \"unaffected\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"description\": \"CWE-770: Allocation of Resources Without Limits or Throttling\"}]}], \"references\": [{\"url\": \"https://go.dev/issue/80481\"}, {\"url\": \"https://go.dev/cl/803320\"}, {\"url\": \"https://groups.google.com/g/golang-announce/c/94pEornpRlI\"}, {\"url\": \"https://pkg.go.dev/vuln/GO-2026-6088\"}]}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-56859\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-14T15:21:09.615961Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-770\", \"description\": \"CWE-770 Allocation of Resources Without Limits or Throttling\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-14T15:21:41.531Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-56859\", \"assignerOrgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"Go\", \"dateReserved\": \"2026-06-23T15:10:49.353Z\", \"datePublished\": \"2026-08-13T21:58:52.959Z\", \"dateUpdated\": \"2026-08-14T15:21:46.218Z\"}",
      "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.