{ "document": { "aggregate_severity": { "namespace": "https://access.redhat.com/security/updates/classification/", "text": "Moderate" }, "category": "csaf_vex", "csaf_version": "2.0", "distribution": { "text": "Copyright © Red Hat, Inc. All rights reserved.", "tlp": { "label": "WHITE", "url": "https://www.first.org/tlp/" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.", "title": "Terms of Use" } ], "publisher": { "category": "vendor", "contact_details": "https://access.redhat.com/security/team/contact/", "issuing_authority": "Red Hat Product Security is responsible for vulnerability handling across all Red Hat products and services.", "name": "Red Hat Product Security", "namespace": "https://www.redhat.com" }, "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55199.json" } ], "title": "libssh2: libssh2: Denial of Service via crafted SSH_MSG_EXT_INFO message", "tracking": { "current_release_date": "2026-07-05T00:34:17+00:00", "generator": { "date": "2026-07-05T00:34:17+00:00", "engine": { "name": "Red Hat SDEngine", "version": "5.3.1" } }, "id": "CVE-2026-55199", "initial_release_date": "2026-06-17T18:44:00+00:00", "revision_history": [ { "date": "2026-06-17T18:44:00+00:00", "number": "1", "summary": "Initial version" }, { "date": "2026-06-26T19:20:09+00:00", "number": "2", "summary": "Current version" }, { "date": "2026-07-05T00:34:17+00:00", "number": "3", "summary": "Last generated version" } ], "status": "final", "version": "3" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_name", "name": "Red Hat Enterprise Linux 6", "product": { "name": "Red Hat Enterprise Linux 6", "product_id": "red_hat_enterprise_linux_6", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:6" } } } ], "category": "product_family", "name": "Red Hat Enterprise Linux 6" }, { "branches": [ { "category": "product_name", "name": "Red Hat Enterprise Linux 7", "product": { "name": "Red Hat Enterprise Linux 7", "product_id": "red_hat_enterprise_linux_7", "product_identification_helper": { "cpe": "cpe:/o:redhat:enterprise_linux:7" } } } ], "category": "product_family", "name": "Red Hat Enterprise Linux 7" }, { "branches": [ { "category": "product_name", "name": "Red Hat Hardened Images", "product": { "name": "Red Hat Hardened Images", "product_id": "Red Hat Hardened Images", "product_identification_helper": { "cpe": "cpe:/a:redhat:hummingbird:1" } } } ], "category": "product_family", "name": "Red Hat Hardened Images" }, { "category": "product_version", "name": "libssh2-devel", "product": { "name": "libssh2-devel", "product_id": "libssh2-devel", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2-devel" } } }, { "category": "product_version", "name": "libssh2", "product": { "name": "libssh2", "product_id": "libssh2", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2" } } }, { "category": "product_version", "name": "libssh2.src", "product": { "name": "libssh2.src", "product_id": "libssh2.src", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2?arch=src" } } }, { "category": "product_version", "name": "libssh2-docs", "product": { "name": "libssh2-docs", "product_id": "libssh2-docs", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2-docs" } } }, { "branches": [ { "category": "product_version", "name": "libssh2-main@aarch64", "product": { "name": "libssh2-main@aarch64", "product_id": "libssh2-main@aarch64", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2@1.11.1-8.hum1?arch=aarch64&distro=hummingbird-20251124&repository_id=public-hummingbird-aarch64-rpms" } } } ], "category": "architecture", "name": "aarch64" }, { "branches": [ { "category": "product_version", "name": "libssh2-main@src", "product": { "name": "libssh2-main@src", "product_id": "libssh2-main@src", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2@1.11.1-8.hum1?arch=src&distro=hummingbird-20251124&repository_id=public-hummingbird-source-rpms" } } } ], "category": "architecture", "name": "src" }, { "branches": [ { "category": "product_version", "name": "libssh2-main@x86_64", "product": { "name": "libssh2-main@x86_64", "product_id": "libssh2-main@x86_64", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2@1.11.1-8.hum1?arch=x86_64&distro=hummingbird-20251124&repository_id=public-hummingbird-x86_64-rpms" } } } ], "category": "architecture", "name": "x86_64" }, { "branches": [ { "category": "product_version", "name": "libssh2-main@noarch", "product": { "name": "libssh2-main@noarch", "product_id": "libssh2-main@noarch", "product_identification_helper": { "purl": "pkg:rpm/redhat/libssh2-docs@1.11.1-8.hum1?arch=noarch&distro=hummingbird-20251124&repository_id=public-hummingbird-x86_64-rpms" } } } ], "category": "architecture", "name": "noarch" } ], "category": "vendor", "name": "Red Hat" } ], "relationships": [ { "category": "default_component_of", "full_product_name": { "name": "libssh2-main@aarch64 as a component of Red Hat Hardened Images", "product_id": "Red Hat Hardened Images:libssh2-main@aarch64" }, "product_reference": "libssh2-main@aarch64", "relates_to_product_reference": "Red Hat Hardened Images" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-main@noarch as a component of Red Hat Hardened Images", "product_id": "Red Hat Hardened Images:libssh2-main@noarch" }, "product_reference": "libssh2-main@noarch", "relates_to_product_reference": "Red Hat Hardened Images" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-main@src as a component of Red Hat Hardened Images", "product_id": "Red Hat Hardened Images:libssh2-main@src" }, "product_reference": "libssh2-main@src", "relates_to_product_reference": "Red Hat Hardened Images" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-main@x86_64 as a component of Red Hat Hardened Images", "product_id": "Red Hat Hardened Images:libssh2-main@x86_64" }, "product_reference": "libssh2-main@x86_64", "relates_to_product_reference": "Red Hat Hardened Images" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2 as a component of Red Hat Enterprise Linux 6", "product_id": "red_hat_enterprise_linux_6:libssh2" }, "product_reference": "libssh2", "relates_to_product_reference": "red_hat_enterprise_linux_6" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-devel as a component of Red Hat Enterprise Linux 6", "product_id": "red_hat_enterprise_linux_6:libssh2-devel" }, "product_reference": "libssh2-devel", "relates_to_product_reference": "red_hat_enterprise_linux_6" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-docs as a component of Red Hat Enterprise Linux 6", "product_id": "red_hat_enterprise_linux_6:libssh2-docs" }, "product_reference": "libssh2-docs", "relates_to_product_reference": "red_hat_enterprise_linux_6" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2.src as a component of Red Hat Enterprise Linux 6", "product_id": "red_hat_enterprise_linux_6:libssh2.src" }, "product_reference": "libssh2.src", "relates_to_product_reference": "red_hat_enterprise_linux_6" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2 as a component of Red Hat Enterprise Linux 7", "product_id": "red_hat_enterprise_linux_7:libssh2" }, "product_reference": "libssh2", "relates_to_product_reference": "red_hat_enterprise_linux_7" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-devel as a component of Red Hat Enterprise Linux 7", "product_id": "red_hat_enterprise_linux_7:libssh2-devel" }, "product_reference": "libssh2-devel", "relates_to_product_reference": "red_hat_enterprise_linux_7" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2-docs as a component of Red Hat Enterprise Linux 7", "product_id": "red_hat_enterprise_linux_7:libssh2-docs" }, "product_reference": "libssh2-docs", "relates_to_product_reference": "red_hat_enterprise_linux_7" }, { "category": "default_component_of", "full_product_name": { "name": "libssh2.src as a component of Red Hat Enterprise Linux 7", "product_id": "red_hat_enterprise_linux_7:libssh2.src" }, "product_reference": "libssh2.src", "relates_to_product_reference": "red_hat_enterprise_linux_7" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-55199", "cwe": { "id": "CWE-606", "name": "Unchecked Input for Loop Condition" }, "discovery_date": "2026-06-17T20:01:26.309958+00:00", "ids": [ { "system_name": "Red Hat Bugzilla ID", "text": "2490128" } ], "notes": [ { "category": "description", "text": "A vulnerability in libssh2 allows a malicious SSH server to freeze connected clients during the handshake process. By sending a malformed packet, the server triggers a loop that exhausts the client's CPU, resulting in a denial of service.", "title": "Vulnerability description" }, { "category": "summary", "text": "libssh2: libssh2: Denial of Service via crafted SSH_MSG_EXT_INFO message", "title": "Vulnerability summary" }, { "category": "other", "text": "A Moderate-rated denial of service vulnerability in the libssh2 client allows a malicious SSH server to freeze the connecting application. By triggering an infinite CPU loop during the initial connection handshake, the server can render the client unresponsive. Note: Red Hat Enterprise Linux (RHEL) 8 and newer are not affected by this flaw, as they do not ship the libssh2 package.", "title": "Statement" }, { "category": "general", "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.", "title": "CVSS score applicability" } ], "product_status": { "fixed": [ "Red Hat Hardened Images:libssh2-main@aarch64", "Red Hat Hardened Images:libssh2-main@noarch", "Red Hat Hardened Images:libssh2-main@src", "Red Hat Hardened Images:libssh2-main@x86_64" ], "known_affected": [ "red_hat_enterprise_linux_6:libssh2", "red_hat_enterprise_linux_6:libssh2-devel", "red_hat_enterprise_linux_6:libssh2-docs", "red_hat_enterprise_linux_6:libssh2.src", "red_hat_enterprise_linux_7:libssh2", "red_hat_enterprise_linux_7:libssh2-devel", "red_hat_enterprise_linux_7:libssh2-docs", "red_hat_enterprise_linux_7:libssh2.src" ] }, "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://access.redhat.com/security/cve/CVE-2026-55199" }, { "category": "external", "summary": "RHBZ#2490128", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2490128" }, { "category": "external", "summary": "https://www.cve.org/CVERecord?id=CVE-2026-55199", "url": "https://www.cve.org/CVERecord?id=CVE-2026-55199" }, { "category": "external", "summary": "https://nvd.nist.gov/vuln/detail/CVE-2026-55199", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55199" }, { "category": "external", "summary": "https://github.com/libssh2/libssh2/commit/17626857d20b3c9a1addfa45979dadcee1cd84a4", "url": "https://github.com/libssh2/libssh2/commit/17626857d20b3c9a1addfa45979dadcee1cd84a4" }, { "category": "external", "summary": "https://github.com/libssh2/libssh2/pull/1864", "url": "https://github.com/libssh2/libssh2/pull/1864" }, { "category": "external", "summary": "https://www.vulncheck.com/advisories/libssh2-pre-authentication-dos-via-ssh-msg-ext-info-handler", "url": "https://www.vulncheck.com/advisories/libssh2-pre-authentication-dos-via-ssh-msg-ext-info-handler" } ], "release_date": "2026-06-17T18:44:00+00:00", "remediations": [ { "category": "vendor_fix", "date": "2026-06-25T13:02:46+00:00", "details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\nhttps://images.redhat.com/", "product_ids": [ "Red Hat Hardened Images:libssh2-main@aarch64", "Red Hat Hardened Images:libssh2-main@noarch", "Red Hat Hardened Images:libssh2-main@src", "Red Hat Hardened Images:libssh2-main@x86_64" ], "url": "https://access.redhat.com/errata/RHSA-2026:29950" }, { "category": "workaround", "details": "To mitigate this issue, ensure your libssh2 clients only connect to trusted SSH servers. You can enforce this by implementing outbound network access controls (egress filtering) to block applications from initiating connections to unknown or untrusted external hosts.", "product_ids": [ "Red Hat Hardened Images:libssh2-main@aarch64", "Red Hat Hardened Images:libssh2-main@noarch", "Red Hat Hardened Images:libssh2-main@src", "Red Hat Hardened Images:libssh2-main@x86_64", "red_hat_enterprise_linux_6:libssh2", "red_hat_enterprise_linux_6:libssh2-devel", "red_hat_enterprise_linux_6:libssh2-docs", "red_hat_enterprise_linux_6:libssh2.src", "red_hat_enterprise_linux_7:libssh2", "red_hat_enterprise_linux_7:libssh2-devel", "red_hat_enterprise_linux_7:libssh2-docs", "red_hat_enterprise_linux_7:libssh2.src" ] }, { "category": "no_fix_planned", "details": "Out of support scope", "product_ids": [ "red_hat_enterprise_linux_6:libssh2", "red_hat_enterprise_linux_6:libssh2-devel", "red_hat_enterprise_linux_6:libssh2-docs", "red_hat_enterprise_linux_6:libssh2.src", "red_hat_enterprise_linux_7:libssh2", "red_hat_enterprise_linux_7:libssh2-devel", "red_hat_enterprise_linux_7:libssh2-docs", "red_hat_enterprise_linux_7:libssh2.src" ] } ], "scores": [ { "cvss_v3": { "attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1" }, "products": [ "Red Hat Hardened Images:libssh2-main@aarch64", "Red Hat Hardened Images:libssh2-main@noarch", "Red Hat Hardened Images:libssh2-main@src", "Red Hat Hardened Images:libssh2-main@x86_64", "red_hat_enterprise_linux_6:libssh2", "red_hat_enterprise_linux_6:libssh2-devel", "red_hat_enterprise_linux_6:libssh2-docs", "red_hat_enterprise_linux_6:libssh2.src", "red_hat_enterprise_linux_7:libssh2", "red_hat_enterprise_linux_7:libssh2-devel", "red_hat_enterprise_linux_7:libssh2-docs", "red_hat_enterprise_linux_7:libssh2.src" ] } ], "threats": [ { "category": "impact", "details": "Moderate", "product_ids": [ "Red Hat Hardened Images:libssh2-main@aarch64", "Red Hat Hardened Images:libssh2-main@noarch", "Red Hat Hardened Images:libssh2-main@src", "Red Hat Hardened Images:libssh2-main@x86_64", "red_hat_enterprise_linux_6:libssh2", "red_hat_enterprise_linux_6:libssh2-devel", "red_hat_enterprise_linux_6:libssh2-docs", "red_hat_enterprise_linux_6:libssh2.src", "red_hat_enterprise_linux_7:libssh2", "red_hat_enterprise_linux_7:libssh2-devel", "red_hat_enterprise_linux_7:libssh2-docs", "red_hat_enterprise_linux_7:libssh2.src" ] } ], "title": "libssh2: libssh2: Denial of Service via crafted SSH_MSG_EXT_INFO message" } ] }