{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-59845", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-07-07T15:40:24.561Z", "datePublished": "2026-07-21T11:26:43.884Z", "dateUpdated": "2026-07-21T11:42:09.438Z"}, "containers": {"cna": {"title": "Libssh: libssh: denial of service via unchecked proxycommand fork() failure", "metrics": [{"other": {"content": {"value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "A flaw was found in libssh. When ProxyCommand is used, an unchecked fork() failure can be stored as process ID -1; during cleanup, signals may then be sent across the caller's accessible process tree, leading to local denial of service."}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "libssh", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:10"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "libssh", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:8"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "libssh", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}, {"vendor": "Red Hat", "product": "Red Hat Hardened Images", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "libssh", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:hummingbird:1"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-59845", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2498178", "name": "RHBZ#2498178", "tags": ["issue-tracking", "x_refsource_REDHAT"]}], "datePublic": "2026-07-21T11:23:44.480Z", "workarounds": [{"lang": "en", "value": "To mitigate this issue, avoid using the ProxyCommand feature in libssh client configurations. This prevents the vulnerable code path from being exercised, thereby eliminating the risk of local denial of service due to unchecked fork() failures."}], "timeline": [{"lang": "en", "time": "2026-04-29T10:03:47.442Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-07-21T11:23:44.480Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Red Hat would like to thank Halil Oktay (oblivionsage) for reporting this issue."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-07-21T11:42:09.438Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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{"acknowledgement": "Red Hat would like to thank Halil Oktay (oblivionsage) for reporting this issue.", "bugzilla": {"description": "libssh: libssh: denial of service via unchecked ProxyCommand fork() failure", "id": "2498178", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2498178"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H", "status": "draft"}, "details": ["A flaw was found in libssh. When ProxyCommand is used, an unchecked fork() failure can be stored as process ID -1; during cleanup, signals may then be sent across the caller's accessible process tree, leading to local denial of service."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, avoid using the ProxyCommand feature in libssh client configurations. This prevents the vulnerable code path from being exercised, thereby eliminating the risk of local denial of service due to unchecked fork() failures."}, "name": "CVE-2026-59845", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "libssh", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "libssh", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "libssh", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "impact": "low", "package_name": "libssh", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-07-21T11:23:44Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-59845\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-59845"], "statement": "This Moderate flaw in libssh client-side ProxyCommand handling can lead to a local denial of service. When ProxyCommand is configured, an unchecked fork() failure may result in signals being sent across the process tree, disrupting local system availability. This issue specifically impacts environments utilizing ProxyCommand functionality.", "threat_severity": "Moderate"}

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