{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-29785", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-04T16:26:02.899Z", "datePublished": "2026-03-25T19:38:44.587Z", "dateUpdated": "2026-03-25T19:40:51.282Z"}, "containers": {"cna": {"title": "NATS Server panic via malicious compression on leafnode port", "problemTypes": [{"descriptions": [{"cweId": "CWE-476", "lang": "en", "description": "CWE-476: NULL Pointer Dereference", "type": "CWE"}]}], "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"}}], "references": [{"name": "https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6"}, {"name": "https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8", "tags": ["x_refsource_MISC"], "url": "https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8"}, {"name": "https://advisories.nats.io/CVE/secnote-2026-04.txt", "tags": ["x_refsource_MISC"], "url": "https://advisories.nats.io/CVE/secnote-2026-04.txt"}], "affected": [{"vendor": "nats-io", "product": "nats-server", "versions": [{"version": "< 2.11.14", "status": "affected"}, {"version": ">= 2.12.0-RC.1, < 2.12.5", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-25T19:40:51.282Z"}, "descriptions": [{"lang": "en", "value": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the \"leafnode\" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port."}], "source": {"advisory": "GHSA-52jh-2xxh-pwh6", "discovery": "UNKNOWN"}}}}

{}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "matchCriteriaId": "4AC9CDDF-79F4-406A-8BD9-B19953A76A4F", "versionEndExcluding": "2.11.14", "vulnerable": true}, {"criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "matchCriteriaId": "B141DA72-3502-4746-A246-EE1087C993F4", "versionEndExcluding": "2.12.5", "versionStartIncluding": "2.12.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the \"leafnode\" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port."}], "id": "CVE-2026-29785", "lastModified": "2026-03-26T17:13:31.983", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-25T20:16:30.373", "references": [{"source": "security-advisories@github.com", "tags": ["Mitigation", "Vendor Advisory"], "url": "https://advisories.nats.io/CVE/secnote-2026-04.txt"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8"}, {"source": "security-advisories@github.com", "tags": ["Mitigation", "Vendor Advisory"], "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "github.com/nats-io/nats-server: NATS-Server: Denial of Service via leafnode compression", "id": "2451444", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2451444"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-409", "details": ["A flaw was found in NATS-Server. A remote attacker can exploit this vulnerability by connecting to a NATS-Server instance where the 'leafnode' configuration is enabled and compression is active. This pre-authentication flaw allows the attacker to trigger a server crash, resulting in a Denial of Service (DoS) for the affected system."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-29785", "package_state": [{"cpe": "cpe:/a:redhat:multicluster_globalhub", "fix_state": "Affected", "package_name": "multicluster-globalhub/multicluster-globalhub-grafana-rhel9", "product_name": "Multicluster Global Hub"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift4/oc-mirror-plugin-rhel9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-03-25T19:38:44Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-29785\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-29785\nhttps://advisories.nats.io/CVE/secnote-2026-04.txt\nhttps://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8\nhttps://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.11.14)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.12.0-RC.1,2.12.5)"}}], "enrichment": {"confidence": 91.0, "confidence_source": "matching", "scores": [{"score": 91.0, "source": "matching"}]}, "original": {"product": "nats-server", "source": "cna", "vendor": "nats-io"}, "product": "nats_server", "vendor": "nats"}], "analysis": {"en": {"generated_at": "2026-03-26T18:38:35.056740+00:00", "value": {"mitigation_remediation": ["Apply the latest NATS Server release (at least 2.11.14 or 2.12.5) to address the panic condition.", "If a patch cannot be applied immediately, disable compression on the leafnode port in the configuration as a temporary countermeasure.", "Consider disabling leafnode functionality entirely if it is not required for your deployment.", "Monitor server logs for panic events and confirm that the mitigation is effective."], "summary": {"action": "Patch Now", "impact": "Denial of Service via Server Panic"}, "threat_synthesis": {"affected_systems": "The flaw affects the NATS.io NATS Server messaging platform in versions earlier than 2.11.14 and 2.12.5. It is present in any deployment where the leafnode feature is active and the default compression setting is enabled, regardless of the operating system used.", "description_and_impact": "An unauthenticated attacker who can connect to a NATS Server that has leafnode configuration enabled can send specialized compressed data that triggers a server panic, immediately crashing the process and disrupting messaging operations. The result is a denial of service with no direct data exposure or code execution; the weakness aligns with the identified CWEs, reflecting erroneous resource handling and null pointer usage.", "risk_and_exploitability": "The CVSS score of 7.5 denotes high severity, while the EPSS score of less than 1% indicates a low likelihood of exploitation, and the vulnerability is not listed in the CISA KEV catalog. The attack requires only network connectivity to the leafnode port and occurs before authentication; thus the attack vector is remote, making broad network exposure a critical concern."}}}}, "created": "2026-03-25T21:46:24.067816+00:00", "updated": "2026-03-27T09:30:15.506946+00:00", "vendors": ["nats", "nats$PRODUCT$nats_server"]}