{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2021-0257", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-0257", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2021-04-22T19:37:17.394Z", "updatedAt": "2024-09-17T01:20:53.966Z", "importedAt": "2026-10-24T01:56:21.187Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "Junos OS: MX Series, EX9200 Series: Trio-based MPCs memory leak in VPLS with integrated routing and bridging (IRB) interface", "summary": "On Juniper Networks MX Series and EX9200 Series platforms with Trio-based MPCs (Modular Port Concentrators) where Integrated Routing and Bridging (IRB) interfaces are configured and mapped to a VPLS instance or a Bridge-Domain, certain Layer 2 network events at Customer Edge (CE) devices may cause memory leaks in the MPC of Provider Edge (PE) devices which can cause an out of memory condition and MPC restart. When this issue occurs, there will be temporary traffic interruption until the MPC is restored. An administrator can use the following CLI command to monitor the status of memory usage level of the MPC: user@device> show system resource-monitor fpc FPC Resource Usage Summary Free Heap Mem Watermark : 20 % Free NH Mem Watermark : 20 % Free Filter Mem Watermark : 20 % * - Watermark reached Slot # % Heap Free RTT Average RTT 1 87 PFE # % ENCAP mem Free % NH mem Free % FW mem Free 0 NA 88 99 1 NA 89 99 When the issue is occurring, the value of “% NH mem Free” will go down until the MPC restarts. This issue affects MX Series and EX9200 Series with Trio-based PFEs (Packet Forwarding Engines), including MX-MPC1-3D, MX-MPC1E-3D, MX-MPC2-3D, MX-MPC2E-3D, MPC-3D-16XGE, and CHAS-MXxx Series MPCs. No other products or platforms are affected by this issue. This issue affects Juniper Networks Junos OS on MX Series, EX9200 Series: 17.3 versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R3-S3; 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R3-S6; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S2, 19.4R3; 20.2 versions prior to 20.2R1-S3, 20.2R2; 20.3 versions prior to 20.3R1-S1,, 20.3R2. This issue does not affect Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R3-S2; 18.1; 18.2 versions prior to 18.2R3-S4; 18.3 versions prior to 18.3R3-S2; 18.4 versions prior to 18.4R3-S1; 19.1; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3; 19.4 versions prior to 19.4R2.", "affected": [ { "vendor": "Juniper Networks", "product": "Junos OS", "platforms": [ "MX Series, EX9200 Series" ], "versions": [ { "version": "17.3", "status": "affected", "versionType": "custom", "lessThan": "17.3R3-S10" }, { "version": "17.4", "status": "affected", "versionType": "custom", "lessThan": "17.4R3-S3" }, { "version": "18.2", "status": "affected", "versionType": "custom", "lessThan": "18.2R3-S7" }, { "version": "18.3", "status": "affected", "versionType": "custom", "lessThan": "18.3R3-S4" }, { "version": "18.4", "status": "affected", "versionType": "custom", "lessThan": "18.4R3-S6" }, { "version": "19.2", "status": "affected", "versionType": "custom", "lessThan": "19.2R3-S2" }, { "version": "19.3", "status": "affected", "versionType": "custom", "lessThan": "19.3R3-S1" }, { "version": "19.4", "status": "affected", "versionType": "custom", "lessThan": "19.4R2-S2, 19.4R3" }, { "version": "20.2", "status": "affected", "versionType": "custom", "lessThan": "20.2R1-S3, 20.2R2" }, { "version": "20.3", "status": "affected", "versionType": "custom", "lessThan": "20.3R1-S1,, 20.3R2" } ] }, { "vendor": "Juniper Networks", "product": "Junos OS", "versions": [ { "version": "18.1", "status": "unaffected" }, { "version": "19.1", "status": "unaffected" }, { "version": "17.3", "status": "unaffected", "versionType": "custom", "lessThan": "17.3R3-S8" }, { "version": "17.4", "status": "unaffected", "versionType": "custom", "lessThan": "17.4R3-S2" }, { "version": "18.2", "status": "unaffected", "versionType": "custom", "lessThan": "18.2R3-S4" }, { "version": "18.3", "status": "unaffected", "versionType": "custom", "lessThan": "18.3R3-S2" }, { "version": "18.4", "status": "unaffected", "versionType": "custom", "lessThan": "18.4R3-S1" }, { "version": "19.2", "status": "unaffected", "versionType": "custom", "lessThan": "19.2R2" }, { "version": "19.3", "status": "unaffected", "versionType": "custom", "lessThan": "19.3R3" }, { "version": "19.4", "status": "unaffected", "versionType": "custom", "lessThan": "19.4R2" } ] } ] } } }