{"id":"CVE-2026-48748","aliases":["DEBIAN-CVE-2026-48748","EUVD-2026-36459","GHSA-4grm-h2qv-h6w6","GHSA-c2rx-5r8w-8xr2","GHSA-hpcc-26xq-25fv","RHLW-2026-ebef76b1d44dd738","UBUNTU-CVE-2026-48748"],"status":"published","title":"Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00392,"percentile":0.33733,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-06-12T14:45:04Z","modified":"2026-11-06T19:30:02Z","fixes":[{"ecosystem":"Maven","package":"io.netty:netty-codec-http3","fixed_in":["4.2.15.Final"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Maven","package":"io.netty:netty-codec-http3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Final"},{"last_affected":"4.2.14.Final"},{"fixed":"4.2.15.Final"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-11","1:4.1.48-12","1:4.1.48-13","1:4.1.48-14","1:4.1.48-15","1:4.1.48-16","1:4.1.48-7","1:4.1.48-7+deb12u1","1:4.1.48-7+deb12u2","1:4.1.48-8","1:4.1.48-9"]},{"source":"osv","ecosystem":"Debian:13","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-10+deb13u1","1:4.1.48-11","1:4.1.48-12","1:4.1.48-13","1:4.1.48-14","1:4.1.48-15","1:4.1.48-16"]},{"source":"osv","ecosystem":"Debian:14","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-11","1:4.1.48-12","1:4.1.48-13","1:4.1.48-14","1:4.1.48-15","1:4.1.48-16"]},{"source":"osv","ecosystem":"Maven","package":"io.netty:netty-codec-http3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Final"},{"fixed":"4.2.15.Final"}]}],"versions":["4.2.10.Final","4.2.11.Final","4.2.12.Final","4.2.13.Final","4.2.14.Final","4.2.2.Final","4.2.3.Final","4.2.4.Final","4.2.5.Final","4.2.6.Final","4.2.7.Final","4.2.8.Final","4.2.9.Final"]},{"source":"osv","ecosystem":"Red Hat Lightwell:Maven","package":"io.netty:netty-codec-http3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.13.Final-rhlw-00001"}]}],"versions":["4.2.10.Final","4.2.11.Final","4.2.12.Final","4.2.13.Final","4.2.2.Final","4.2.3.Final","4.2.4.Final","4.2.5.Final","4.2.6.Final","4.2.7.Final","4.2.8.Final","4.2.9.Final"],"bundled":3},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:3.2.6.Final-2","1:3.2.6.Final-2+deb8u2build0.14.04.1~esm1","1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:3.2.6.Final-2","1:4.0.32-1","1:4.0.33-1","1:4.0.34-1","1:4.0.34-1ubuntu0.1~esm1","1:4.0.34-1ubuntu0.1~esm2","1:4.0.34-1ubuntu0.1~esm3","1:4.0.34-1ubuntu0.1~esm4","1:4.0.34-1ubuntu0.1~esm5"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.7-4","1:4.1.7-4ubuntu0.1~esm1","1:4.1.7-4ubuntu0.1","1:4.1.7-4ubuntu0.1+esm1","1:4.1.7-4ubuntu0.1+esm2","1:4.1.7-4ubuntu0.1+esm3","1:4.1.7-4ubuntu0.1+esm4","1:4.1.7-4ubuntu0.1+esm5","1:4.1.7-4ubuntu0.1+esm6","1:4.1.7-4ubuntu0.1+esm7"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.33-1","1:4.1.33-2","1:4.1.33-3","1:4.1.45-1","1:4.1.45-1ubuntu0.1~esm1","1:4.1.45-1ubuntu0.1~esm2","1:4.1.45-1ubuntu0.1~esm3","1:4.1.45-1ubuntu0.1~esm4","1:4.1.45-1ubuntu0.1~esm6","1:4.1.45-1ubuntu0.1~esm7"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-4","1:4.1.48-4+deb11u1build0.22.04.1","1:4.1.48-4+deb11u2build0.22.04.1","1:4.1.48-4+deb11u2ubuntu0.1~esm1","1:4.1.48-4+deb11u2ubuntu0.1~esm2","1:4.1.48-4+deb11u2ubuntu0.1","1:4.1.48-4+deb11u2ubuntu0.1+esm1","1:4.1.48-4+deb11u2ubuntu0.1+esm3","1:4.1.48-4+deb11u2ubuntu0.2","1:4.1.48-4+deb11u2ubuntu0.2+esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-7","1:4.1.48-8","1:4.1.48-9","1:4.1.48-9ubuntu0.1~esm1","1:4.1.48-9ubuntu0.1~esm2","1:4.1.48-9ubuntu0.1","1:4.1.48-9ubuntu0.1+esm1","1:4.1.48-9ubuntu0.1+esm3","1:4.1.48-9ubuntu0.2","1:4.1.48-9ubuntu0.2+esm1","1:4.1.48-9ubuntu0.2+esm2"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-10ubuntu0.25.10.1","1:4.1.48-10ubuntu0.25.10.2"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-16","1:4.1.48-16ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:26.04:LTS","package":"netty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:4.1.48-10","1:4.1.48-11","1:4.1.48-12","1:4.1.48-13","1:4.1.48-14","1:4.1.48-16","1:4.1.48-16ubuntu0.1~esm2"]}],"products":[{"vendor":"netty","product":"netty"},{"vendor":"red hat","product":"red hat build of apache camel - hawtio 4"}],"references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-4grm-h2qv-h6w6","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web","report"]},{"url":"https://github.com/netty/netty/commit/75127cab731ee35068d1f0667bffa188bc332f5d","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final","tags":["x_refsource_MISC","Release Notes","web","report"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-48748","tags":["vdb-entry","x_refsource_REDHAT","advisory","web"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2488441","tags":["issue-tracking","x_refsource_REDHAT","report","web"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48748.json","tags":["x_sadp-csaf-vex","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48748","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-4grm-h2qv-h6w6","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48748.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-48748","tags":["advisory"]},{"url":"https://github.com/netty/netty","tags":["package"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44892.json","tags":["advisory"]},{"url":"https://github.com/netty/netty/security/advisories/GHSA-c2rx-5r8w-8xr2","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44892","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-c2rx-5r8w-8xr2","tags":["advisory"]},{"url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56816.json","tags":["advisory"]},{"url":"https://github.com/netty/netty/security/advisories/GHSA-hpcc-26xq-25fv","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56816","tags":["advisory"]},{"url":"https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b","tags":["fix"]},{"url":"https://github.com/advisories/GHSA-hpcc-26xq-25fv","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-48748","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-48748","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-48748","title":"Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T14:45:04.763Z","modified":"2026-08-04T21:49:40.894Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"adp"}],"cwes":["CWE-770","CWE-770"],"updated_at":"2026-11-02T13:50:49.872037Z"}],"euvd":[{"id":"EUVD-2026-36459","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T14:45:04Z","modified":"2026-08-04T21:49:40Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T18:02:22.516769Z"}],"ghsa":[{"id":"GHSA-4grm-h2qv-h6w6","title":"Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion","description":"### Summary\nA memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error.\n\n### Details\nThe vulnerability exists in `io.netty.handler.codec.http3.QpackDecoder#shouldWaitForDynamicTableUpdates`:\n\nIf a client sends a header referencing a table entry that the server hasn't received yet, the server must pause that stream and wait for the missing entry to arrive. To prevent attackers from exhausting resources by intentionally sending missing references, Netty limits the number of streams that can be blocked at the same time.\n\nHowever, the check is implemented as:\n\n```java\nif (blockedStreamsCount == maxBlockedStreams - 1) {\n```\n\nIf the server enables QPACK dynamic tables (by setting `HTTP3_SETTINGS_QPACK_MAX_TABLE_CAPACITY` \u003e 0) but does not explicitly configure `HTTP3_SETTINGS_QPACK_BLOCKED_STREAMS`, it defaults to 0.\n\nWhen `maxBlockedStreams` is 0, the condition evaluates to `blockedStreamsCount == -1`. Since `blockedStreamsCount` starts at `0` and only increments, it never equals `-1`. This bypasses the limit, allowing an attacker to open an infinite number of streams that block indefinitely. Additionally, the `QpackDecoder` never removes unblocked streams from the `blockedStreams` map or decrements the counter, meaning the `ReadResumptionListener` for each blocked stream is kept in memory for the entire lifetime of the connection. This exhausts server memory and crashes the JVM.\n\n### Impact\nDenial of Service. Any server using `netty-codec-http3` with QPACK dynamic tables enabled and maxBlockedStreams defaulting to 0 is impacted.","status":"published","published":"2026-06-15T20:43:13Z","modified":"2026-08-04T21:50:04Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:40:56.852119Z"}],"nvd":[{"id":"CVE-2026-48748","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T16:16:30.913Z","modified":"2026-08-04T22:17:15Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:23.846948Z"}],"osv":[{"id":"CVE-2026-48748","title":"Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T14:45:04.763Z","modified":"2026-10-28T10:55:26.059464291Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"DEBIAN-CVE-2026-48748","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T16:16:30.913Z","modified":"2026-10-01T03:03:07.076936731Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:56.444225Z"},{"id":"GHSA-4grm-h2qv-h6w6","title":"Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion","description":"### Summary\nA memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error.\n\n### Details\nThe vulnerability exists in `io.netty.handler.codec.http3.QpackDecoder#shouldWaitForDynamicTableUpdates`:\n\nIf a client sends a header referencing a table entry that the server hasn't received yet, the server must pause that stream and wait for the missing entry to arrive. To prevent attackers from exhausting resources by intentionally sending missing references, Netty limits the number of streams that can be blocked at the same time.\n\nHowever, the check is implemented as:\n\n```java\nif (blockedStreamsCount == maxBlockedStreams - 1) {\n```\n\nIf the server enables QPACK dynamic tables (by setting `HTTP3_SETTINGS_QPACK_MAX_TABLE_CAPACITY` \u003e 0) but does not explicitly configure `HTTP3_SETTINGS_QPACK_BLOCKED_STREAMS`, it defaults to 0.\n\nWhen `maxBlockedStreams` is 0, the condition evaluates to `blockedStreamsCount == -1`. Since `blockedStreamsCount` starts at `0` and only increments, it never equals `-1`. This bypasses the limit, allowing an attacker to open an infinite number of streams that block indefinitely. Additionally, the `QpackDecoder` never removes unblocked streams from the `blockedStreams` map or decrements the counter, meaning the `ReadResumptionListener` for each blocked stream is kept in memory for the entire lifetime of the connection. This exhausts server memory and crashes the JVM.\n\n### Impact\nDenial of Service. Any server using `netty-codec-http3` with QPACK dynamic tables enabled and maxBlockedStreams defaulting to 0 is impacted.","status":"published","published":"2026-06-15T20:43:13Z","modified":"2026-09-10T03:50:48.196030192Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:37.148947Z"},{"id":"RHLW-2026-ebef76b1d44dd738","title":"Lightwell Security Advisory: netty-codec-http3 4.2.13.Final-rhlw-00001","description":"Red Hat Lightwell has released io.netty:netty-codec-http3 4.2.13.Final-rhlw-00001 with backported fixes for CVE-2026-44892, CVE-2026-48748, and CVE-2026-56816.\n\nCVE-2026-44892: Netty has a Vulnerable Default Configuration Which Leads to Denial of Service via Unbounded HTTP/3 Header Size\n\nCVE-2026-48748: Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion\n\nCVE-2026-56816: Netty: Memory Exhaustion via HTTP/3 Reserved Frame Types\n\nThis patched artifact is a drop-in replacement for io.netty:netty-codec-http3 4.2.13.Final-rhlw-00001 from Maven Central.","status":"published","published":"2026-11-06T08:56:08Z","modified":"2026-11-06T19:43:10.519147666Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-06T20:08:20.701853Z"},{"id":"UBUNTU-CVE-2026-48748","description":"Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.","status":"published","published":"2026-06-12T16:16:00Z","modified":"2026-10-17T12:58:31.220815811Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T16:56:33.391918Z"}]}}