{"answers":{"affected":"4 open source packages ship an affected version, including io.netty:netty-codec-http2. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56819 exists.","fix":"Upgrade io.netty:netty-codec-http2 to a fixed version for your release line: 4.1.136.Final or 4.2.16.Final.","what":"CVE-2026-56819 is a high-severity denial of service vulnerability in Netty Netty, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-56819 and fix it if it is affected.\n\nWhat it is: CVE-2026-56819 is a high-severity denial of service vulnerability in Netty Netty, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56819 exists.\n\nAffected packages and fixed versions:\n- io.netty:netty-codec-http2 (Maven): affected from 4.1.0.Final; fixed in 4.1.136.Final\n- io.netty:netty-codec-http2 (Maven): affected from 4.1.0.Final; fixed in 4.1.136.Final\n- io.netty:netty-codec-http2 (Maven): affected from 4.2.0; fixed in 4.2.16.Final\n- io.netty:netty-codec-http2 (Maven): affected from 4.2.0; fixed in 4.2.16.Final\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-56819/ (Markdown: https://insights.sbomify.com/CVE-2026-56819/index.md)","id":"CVE-2026-56819","markdown":"https://insights.sbomify.com/CVE-2026-56819/index.md","name":"CVE-2026-56819","record":{"aliases":["CLEANSTART-2026-CP47219","CLEANSTART-2026-DG55776","CLEANSTART-2026-PW77376","CLEANSTART-2026-TY09465","DEBIAN-CVE-2026-56819","ECHO-7258-9374-4a42","GHSA-93wv-jw9v-4972","MINI-27h3-p4qw-h4gh","MINI-2c43-742m-h97j","MINI-2gp5-jhrg-f6p6","MINI-2jvv-jwrj-6wv4","MINI-2r4q-x97q-jp6r","MINI-339c-5vr4-rj6w","MINI-3fr7-vcmw-vhp6","MINI-3q8j-g2wc-qpgp","MINI-3wmx-qc5r-m7cv","MINI-44pv-2m65-c8gx","MINI-489r-r39g-ghjq","MINI-4gpv-r4ph-rrpp","MINI-524f-5hv3-chfg","MINI-5r55-wm7p-7jhc","MINI-62wq-cmhj-r95r","MINI-63cf-2rpw-vc6r","MINI-63xg-jfvc-r589","MINI-683r-pfj7-w47g","MINI-6f2w-7m8x-5wv5","MINI-6ggm-62h2-hjg3","MINI-6qr5-9g6v-vp56","MINI-72x7-qppw-jvjx","MINI-77m5-6m78-f8fx","MINI-77vw-8wvw-cv8m","MINI-78p7-qqhh-7q6x","MINI-7cpc-mw56-wp83","MINI-7f4h-7rxx-6hq6","MINI-7mjj-wp4g-5p5q","MINI-8pxp-m6hr-qj68","MINI-8x95-fhfc-5mqw","MINI-92rw-4qxq-q2j6","MINI-95xw-7hv5-9v7c","MINI-98fh-3x25-7rmr","MINI-98w3-8mh5-39m4","MINI-994r-cqjm-4w3v","MINI-9r9q-3pp9-rm9v","MINI-c7vj-q6j2-6qrj","MINI-cpvv-phjv-8p3h","MINI-f3cj-fc73-46c5","MINI-f98j-4736-vmjh","MINI-ffr9-xf28-5v73","MINI-fqv3-fhg8-x5h4","MINI-fvf2-prhg-545v","MINI-g299-w585-x845","MINI-g2hq-8pvm-587q","MINI-g4h6-8466-6pfr","MINI-g7xv-gqph-v3fw","MINI-gjhq-fp8m-x9cq","MINI-gmhg-h59g-grgr","MINI-grmc-g52j-xpc7","MINI-j34p-mw47-f9cq","MINI-j7mm-fgxw-xmcr","MINI-jfwg-r447-fp5v","MINI-jhmx-fq28-pch5","MINI-jpwp-895w-wwp6","MINI-jxmq-jc82-jhgg","MINI-m3f7-fgvx-cm8j","MINI-p53m-wx4w-4w7r","MINI-pmff-frq2-3vf4","MINI-ppm4-4736-hfqc","MINI-q97x-7r6x-5r2f","MINI-qfhc-rxxw-8wgr","MINI-qmm3-j99w-h34x","MINI-qxvr-j374-9wvj","MINI-qxwm-73jq-j494","MINI-r5hg-5rf8-w4j8","MINI-rcwp-c54f-f4gh","MINI-rfg5-p3v2-jq7h","MINI-rr86-h535-cvx5","MINI-v33g-547h-cvg9","MINI-v36j-hxhr-vqr8","MINI-v3w8-p678-qpvv","MINI-v4m3-m825-hgm3","MINI-v6fg-5mvh-xmp3","MINI-v6rf-52mc-jvqj","MINI-v823-xcgj-74j8","MINI-vm33-g4vc-35h6","MINI-vmjr-4f68-45vh","MINI-vqhq-chgp-8x88","MINI-w2j6-w6x3-r9xf","MINI-w428-rrg4-r2g6","MINI-w5cf-rcxh-7m7g","MINI-wmgg-6xg2-689q","MINI-x5fm-2f68-jg4c","MINI-x88g-qww6-7gx4","MINI-xxj6-59g8-ccpw","ROOT-APP-MAVEN-CVE-2026-56819","UBUNTU-CVE-2026-56819"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Java network framework","requires_auth":"none","summary":"Remote attackers can cause a denial of service by exhausting direct memory in Netty applications using HTTP/2 decompression.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"netty","vendor":"netty"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-401","name":"Missing Release of Memory after Effective Lifetime"},{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"description":"Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct `ByteBuf` per HTTP/2 `DATA` frame in applications that enable HTTP/2 content decompression via `DelegatingDecompressorFrameListener`. When a `DATA` frame is processed for a stream whose decompressor has already been closed, `Http2Decompressor.decompress(...)` calls `decompressor.writeInbound(data.retain())` and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.","ecosystems":["Maven"],"exploits":{"exploitdb":0,"first_seen":"2026-09-05","github_poc":1,"max_poc_stars":0,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-09-05T16:58:24Z","kind":"github_poc","ref":"https://github.com/xiaoqiMikko/netty-http2-check","stars":0,"title":"CVE-2025-55163 / CVE-2026-56819: offline checker for the 7 netty-codec-http2 CVEs. Tells you which ones you are exposed to, and the one version that fixes all seven (4.1.136.Final / 4.2.16.Final) - written on none of the advisories. Does not scan pom.xml on purpose: WebFlux pulls it in transitively."}],"tier":"weaponised"},"has_fix":true,"headline":"Netty: HTTP/2 decompression leaks ByteBuf reference count when the decompressor channel is already closed (Direct memory leak / OOM DoS)","id":"CVE-2026-56819","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Maven","product":"netty:netty","products":["netty:netty"],"type":"denial_of_service","year":"2026"},"n_packages":4,"n_references":5,"next":{"headline":"Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks","id":"CVE-2026-56820"},"packages":[{"ecosystem":"Maven","fixed":["4.1.136.Final"],"introduced":["4.1.0.Final"],"last_affected":[],"package":"io.netty:netty-codec-http2","purl":null,"source":"GHSA-93wv-jw9v-4972"},{"ecosystem":"Maven","fixed":["4.1.136.Final"],"introduced":["4.1.0.Final"],"last_affected":[],"package":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","source":"GHSA-93wv-jw9v-4972"},{"ecosystem":"Maven","fixed":["4.2.16.Final"],"introduced":["4.2.0"],"last_affected":[],"package":"io.netty:netty-codec-http2","purl":null,"source":"GHSA-93wv-jw9v-4972"},{"ecosystem":"Maven","fixed":["4.2.16.Final"],"introduced":["4.2.0"],"last_affected":[],"package":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","source":"GHSA-93wv-jw9v-4972"}],"prev":{"headline":"Netty: RedisArrayAggregator max-elements failure leaves retained partial aggregate state","id":"CVE-2026-56818"},"products":["netty"],"published":"2026-07-21","related":[{"cvss_score":9.1,"headline":"Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext","id":"CVE-2026-75595","kev_date_added":null,"published":"2026-08-19"},{"cvss_score":8.7,"headline":"Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing","id":"CVE-2026-75596","kev_date_added":null,"published":"2026-08-19"},{"cvss_score":8.7,"headline":"Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang","id":"CVE-2026-59901","kev_date_added":null,"published":"2026-07-29"},{"cvss_score":8.7,"headline":"Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion","id":"CVE-2026-55851","kev_date_added":null,"published":"2026-07-21"},{"cvss_score":8.7,"headline":"Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion","id":"CVE-2026-56745","kev_date_added":null,"published":"2026-07-21"},{"cvss_score":8.7,"headline":"Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records","id":"CVE-2026-45674","kev_date_added":null,"published":"2026-06-12"},{"cvss_score":8.7,"headline":"Netty has Insufficient Bailiwick Validation for NS Records","id":"CVE-2026-47691","kev_date_added":null,"published":"2026-06-12"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-23","vendors":["netty"]},"summary":"Remote attackers can cause a denial of service by exhausting direct memory in Netty applications using HTTP/2 decompression.","url":"https://insights.sbomify.com/CVE-2026-56819/"}