CVE-2026-39822 (GCVE-0-2026-39822)
Vulnerability from cvelistv5 – Published: 2026-07-08 15:46 – Updated: 2026-07-08 19:39
VLAI
EPSS
VEX
Title
Root escape via symlink plus trailing slash in os
Summary
On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root.
Severity
7.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-08 18:06 UTC
CWE
- CWE-61 - UNIX Symbolic Link (Symlink) Following
Assigner
References
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Go standard library | os |
Affected:
0 , < 1.25.12
(semver)
Affected: 1.26.0-0 , < 1.26.5 (semver) Affected: 1.27.0-0 , < 1.27.0-rc.2 (semver) |
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-39822",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-08T18:06:16.360721Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-61",
"description": "CWE-61 UNIX Symbolic Link (Symlink) Following",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-08T19:39:17.341Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "os",
"product": "os",
"programRoutines": [
{
"name": "rootOpenFileNolog"
},
{
"name": "openRootInRoot"
},
{
"name": "OpenInRoot"
},
{
"name": "Root.Create"
},
{
"name": "Root.Open"
},
{
"name": "Root.OpenFile"
},
{
"name": "Root.OpenRoot"
},
{
"name": "Root.ReadFile"
},
{
"name": "Root.WriteFile"
},
{
"name": "rootFS.Open"
},
{
"name": "rootFS.ReadDir"
},
{
"name": "rootFS.ReadFile"
}
],
"vendor": "Go standard library",
"versions": [
{
"lessThan": "1.25.12",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.26.5",
"status": "affected",
"version": "1.26.0-0",
"versionType": "semver"
},
{
"lessThan": "1.27.0-rc.2",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "Mundur (https://github.com/M0nd0R)"
}
],
"descriptions": [
{
"lang": "en",
"value": "On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, \u0027root.Open(\"symlink/\")\u0027 will open \"symlink\" even when \"symlink\" is a symbolic link pointing outside of the root."
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-61: UNIX Symbolic Link (Symlink) Following",
"lang": "en"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-08T15:46:27.199Z",
"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"shortName": "Go"
},
"references": [
{
"url": "https://go.dev/issue/79005"
},
{
"url": "https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc"
},
{
"url": "https://go.dev/cl/797880"
},
{
"url": "https://pkg.go.dev/vuln/GO-2026-4970"
}
],
"title": "Root escape via symlink plus trailing slash in os"
}
},
"cveMetadata": {
"assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"assignerShortName": "Go",
"cveId": "CVE-2026-39822",
"datePublished": "2026-07-08T15:46:27.199Z",
"dateReserved": "2026-04-07T18:13:03.527Z",
"dateUpdated": "2026-07-08T19:39:17.341Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-39822",
"date": "2026-09-17",
"epss": "0.00232",
"percentile": "0.1432"
},
"microsoft_vex": {
"current_release_date": "2026-08-13T00:12:02.000Z",
"cve": "CVE-2026-39822",
"id": "msrc_CVE-2026-39822",
"initial_release_date": "2026-07-15T01:01:36.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "2",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "Root escape via symlink plus trailing slash in os",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-39822.json",
"version": "2"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-39822\",\"sourceIdentifier\":\"security@golang.org\",\"published\":\"2026-07-08T17:17:21.310\",\"lastModified\":\"2026-07-13T14:54:26.317\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, \u0027root.Open(\\\"symlink/\\\")\u0027 will open \\\"symlink\\\" even when \\\"symlink\\\" is a symbolic link pointing outside of the root.\"}],\"affected\":[{\"source\":\"security@golang.org\",\"affectedData\":[{\"vendor\":\"Go standard library\",\"product\":\"os\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://pkg.go.dev\",\"packageName\":\"os\",\"programRoutines\":[{\"name\":\"rootOpenFileNolog\"},{\"name\":\"openRootInRoot\"},{\"name\":\"OpenInRoot\"},{\"name\":\"Root.Create\"},{\"name\":\"Root.Open\"},{\"name\":\"Root.OpenFile\"},{\"name\":\"Root.OpenRoot\"},{\"name\":\"Root.ReadFile\"},{\"name\":\"Root.WriteFile\"},{\"name\":\"rootFS.Open\"},{\"name\":\"rootFS.ReadDir\"},{\"name\":\"rootFS.ReadFile\"}],\"versions\":[{\"version\":\"0\",\"lessThan\":\"1.25.12\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"1.26.0-0\",\"lessThan\":\"1.26.5\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"1.27.0-0\",\"lessThan\":\"1.27.0-rc.2\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-08T18:06:16.360721Z\",\"id\":\"CVE-2026-39822\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-61\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.25.12\",\"matchCriteriaId\":\"BA474C81-2BDB-451D-BAC7-5714B4F30E1F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.26.0\",\"versionEndExcluding\":\"1.26.5\",\"matchCriteriaId\":\"08CDCAED-0C22-42D9-97A8-77F19DEECDB2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:1.27:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"1062DCC7-46FE-4CF5-ADEF-BEC03F8AB39E\"}]}]}],\"references\":[{\"url\":\"https://go.dev/cl/797880\",\"source\":\"security@golang.org\",\"tags\":[\"Patch\"]},{\"url\":\"https://go.dev/issue/79005\",\"source\":\"security@golang.org\",\"tags\":[\"Issue Tracking\",\"Patch\"]},{\"url\":\"https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc\",\"source\":\"security@golang.org\",\"tags\":[\"Mailing List\",\"Patch\",\"Vendor Advisory\"]},{\"url\":\"https://pkg.go.dev/vuln/GO-2026-4970\",\"source\":\"security@golang.org\",\"tags\":[\"Vendor Advisory\"]}]}}",
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-09-15T11:25:21+00:00",
"cve": "CVE-2026-39822",
"id": "CVE-2026-39822",
"initial_release_date": "2026-07-08T15:46:27.199000+00:00",
"product_status:fixed": "415",
"product_status:known_affected": "13",
"product_status:known_not_affected": "505",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "golang: Go os.Root: Symlink following vulnerability allows directory traversal",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39822.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-15T02:08:44Z",
"cve": "CVE-2026-39822",
"id": "CVE-2026-39822",
"initial_release_date": "2026-07-09T03:01:17Z",
"product_status:known_affected": "24",
"product_status:known_not_affected": "76",
"product_status:recommended": "263",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-39822",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-39822.json",
"version": "9"
},
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.8, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-39822\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-08T18:06:16.360721Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-61\", \"description\": \"CWE-61 UNIX Symbolic Link (Symlink) Following\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-08T18:05:38.120Z\"}}], \"cna\": {\"title\": \"Root escape via symlink plus trailing slash in os\", \"credits\": [{\"lang\": \"en\", \"value\": \"Mundur (https://github.com/M0nd0R)\"}], \"affected\": [{\"vendor\": \"Go standard library\", \"product\": \"os\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"1.25.12\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"1.26.0-0\", \"lessThan\": \"1.26.5\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"1.27.0-0\", \"lessThan\": \"1.27.0-rc.2\", \"versionType\": \"semver\"}], \"packageName\": \"os\", \"collectionURL\": \"https://pkg.go.dev\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"rootOpenFileNolog\"}, {\"name\": \"openRootInRoot\"}, {\"name\": \"OpenInRoot\"}, {\"name\": \"Root.Create\"}, {\"name\": \"Root.Open\"}, {\"name\": \"Root.OpenFile\"}, {\"name\": \"Root.OpenRoot\"}, {\"name\": \"Root.ReadFile\"}, {\"name\": \"Root.WriteFile\"}, {\"name\": \"rootFS.Open\"}, {\"name\": \"rootFS.ReadDir\"}, {\"name\": \"rootFS.ReadFile\"}]}], \"references\": [{\"url\": \"https://go.dev/issue/79005\"}, {\"url\": \"https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc\"}, {\"url\": \"https://go.dev/cl/797880\"}, {\"url\": \"https://pkg.go.dev/vuln/GO-2026-4970\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, \u0027root.Open(\\\"symlink/\\\")\u0027 will open \\\"symlink\\\" even when \\\"symlink\\\" is a symbolic link pointing outside of the root.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"description\": \"CWE-61: UNIX Symbolic Link (Symlink) Following\"}]}], \"providerMetadata\": {\"orgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"shortName\": \"Go\", \"dateUpdated\": \"2026-07-08T15:46:27.199Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-39822\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-08T19:39:17.341Z\", \"dateReserved\": \"2026-04-07T18:13:03.527Z\", \"assignerOrgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"datePublished\": \"2026-07-08T15:46:27.199Z\", \"assignerShortName\": \"Go\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…