{"id":"CVE-2026-77021","aliases":["EUVD-2026-83883","GHSA-5q8h-fhcg-2395"],"status":"published","title":"Missing decompression size limit in agent receiver allows memory exhaustion via push agent data","description":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37, \u003c2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00382,"percentile":0.32648,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-409"],"published":"2026-09-21T10:57:37Z","modified":"2026-09-21T20:17:32Z","products":[{"vendor":"checkmk gmbh","product":"checkmk"}],"references":[{"url":"https://checkmk.com/werk/22116","tags":["vendor-advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77021"},{"url":"https://github.com/advisories/GHSA-5q8h-fhcg-2395"}],"sources":{"cve":[{"id":"CVE-2026-77021","title":"Missing decompression size limit in agent receiver allows memory exhaustion via push agent data","description":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37, \u003c2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.","status":"published","published":"2026-09-21T10:57:37.433Z","modified":"2026-09-21T19:40:26.202Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:20:16.072351Z"}],"euvd":[{"id":"EUVD-2026-83883","description":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37, \u003c2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.","status":"published","published":"2026-09-21T10:57:37Z","modified":"2026-09-21T19:40:26Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T17:28:04.224689Z"}],"ghsa":[{"id":"GHSA-5q8h-fhcg-2395","title":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37,...","description":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37, \u003c2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.","status":"published","published":"2026-09-21T12:32:36Z","modified":"2026-09-21T12:32:41Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T15:12:14.750064Z"}],"nvd":[{"id":"CVE-2026-77021","description":"Improper handling of highly compressed data (data amplification) in Checkmk \u003c2.5.0p14, \u003c2.4.0p37, \u003c2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.","status":"published","published":"2026-09-21T11:17:12.2Z","modified":"2026-09-21T20:17:32.393Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:12:50.043898Z"}]}}