{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-26466", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2025-02-10T18:31:47.979Z", "datePublished": "2025-02-28T21:25:28.861Z", "dateUpdated": "2026-06-30T00:24:46.893Z" }, "containers": { "cna": { "title": "Openssh: denial-of-service in openssh", "metrics": [ { "other": { "content": { "value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/" }, "type": "Red Hat severity rating" } }, { "cvssV3_1": { "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" }, "format": "CVSS" } ], "descriptions": [ { "lang": "en", "value": "A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack." } ], "affected": [ { "repo": "https://anongit.mindrot.org/openssh.git", "versions": [ { "status": "affected", "version": "9.5p1", "versionType": "custom", "lessThanOrEqual": "9.9p1" } ], "packageName": "OpenSSH", "collectionURL": "https://www.openssh.com/", "defaultStatus": "unaffected" }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "unaffected", "cpes": [ "cpe:/o:redhat:enterprise_linux:10" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "unaffected", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "unaffected", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openssh", "defaultStatus": "unaffected", "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": "openssh", "defaultStatus": "unaffected", "cpes": [ "cpe:/o:redhat:enterprise_linux:9" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "rhcos", "defaultStatus": "unaffected", "cpes": [ "cpe:/a:redhat:openshift:4" ] } ], "references": [ { "url": "https://access.redhat.com/security/cve/CVE-2025-26466", "tags": [ "vdb-entry", "x_refsource_REDHAT" ] }, { "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2345043", "name": "RHBZ#2345043", "tags": [ "issue-tracking", "x_refsource_REDHAT" ] }, { "url": "https://seclists.org/oss-sec/2025/q1/144" }, { "url": "https://www.qualys.com/2025/02/18/openssh-mitm-dos.txt" } ], "datePublic": "2025-02-18T00:00:00.000Z", "problemTypes": [ { "descriptions": [ { "cweId": "CWE-770", "description": "Allocation of Resources Without Limits or Throttling", "lang": "en", "type": "CWE" } ] } ], "x_redhatCweChain": "CWE-770: Allocation of Resources Without Limits or Throttling", "workarounds": [ { "lang": "en", "value": "This issue can be mitigated by setting the following three different options in the sshd configuration file located at: /etc/ssh/sshd_config\n\nMaxStartups: Set to a reasonable value, this option controls the maximum number of concurrent unauthenticated connections the SSH server accepts;\n\nPerSourcePenalties: Set its suboptions to a reasonable value, this option is used to help sshd to detect and drop connections that are potentially malicious for the SSH server;\n\nLoginGraceTime: Set to a resonable value, this option controls how much time the SSH server will wait the client to authenticate before dropping its connection;\n\nAll the three option above needs to be set to implement a full mitigation for this vulnerability." } ], "timeline": [ { "lang": "en", "time": "2025-02-11T19:51:30.375Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2025-02-18T00:00:00.000Z", "value": "Made public." } ], "providerMetadata": { "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-06-30T00:24:46.893Z" }, "x_generator": { "engine": "cvelib 1.8.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-02-10T17:13:57.386Z" }, "references": [ { "url": "https://security.netapp.com/advisory/ntap-20250228-0002/" }, { "url": "https://www.openwall.com/lists/oss-security/2025/02/18/1" }, { "url": "https://www.openwall.com/lists/oss-security/2025/02/18/4" }, { "url": "https://bugzilla.suse.com/show_bug.cgi?id=1237041" }, { "url": "https://security-tracker.debian.org/tracker/CVE-2025-26466" }, { "url": "https://ubuntu.com/security/CVE-2025-26466" }, { "url": "http://seclists.org/fulldisclosure/2025/May/8" }, { "url": "http://seclists.org/fulldisclosure/2025/May/7" }, { "url": "http://seclists.org/fulldisclosure/2025/Feb/18" }, { "url": "https://www.vicarius.io/vsociety/posts/cve-2025-26466-detection-script-memory-consumption-vulnerability-in-openssh" }, { "url": "https://www.vicarius.io/vsociety/posts/cve-2025-26466-mitigation-script-memory-consumption-vulnerability-in-openssh" } ], "title": "CVE Program Container", "x_generator": { "engine": "ADPogram 0.0.1" } }, { "references": [ { "url": 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