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{"bugzilla": {"description": "nginx: NGINX: Arbitrary code execution or Denial of Service via heap-based buffer overflow with crafted HTTP/2 headers", "id": "2489866", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2489866"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-131", "details": ["A flaw was found in NGINX. When NGINX is configured to proxy HTTP/2 traffic using the ngx_http_proxy_v2_module or ngx_http_grpc_module with specific settings, a remote, unauthenticated attacker can send specially crafted large headers. This can trigger a heap-based buffer overflow, leading to a restart of the NGINX worker process and a Denial of Service (DoS). Under certain conditions, such as when Address Space Layout Randomization (ASLR) is disabled or bypassed, this vulnerability could also allow for arbitrary code execution."], "mitigation": {"lang": "en:us", "value": "To mitigate this vulnerability, ensure that the `ignore_invalid_headers` directive is set to `on` in your NGINX configuration, or reduce the size specified by the `large_client_header_buffers` directive to 2 megabytes or less. These changes require an NGINX service reload or restart to take effect. Reloading the NGINX service is generally safe, but a restart will briefly interrupt service."}, "name": "CVE-2026-42055", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "nginx:1.24/nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "nginx:1.26/nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "nginx", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-06-17T14:04:32Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-42055\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-42055\nhttps://my.f5.com/manage/s/article/K000161584"], "statement": "This issue is classified as Important severity primarily because:\nConditions for Exploitation: A remote, unauthenticated attacker can only exploit this if NGINX is explicitly configured to proxy HTTP/2 traffic using the ngx_http_proxy_v2_module or ngx_http_grpc_module.\nImpact Limitations: While the flaw reliably causes a Denial of Service (worker restart), achieving arbitrary code execution is highly complex in modern environments as it requires the attacker to bypass or disable Address Space Layout Randomization (ASLR)", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.13.10,1.31.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.30.2,1.30.3)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "NGINX Open Source", "source": "cna", "vendor": "F5"}, "product": "nginx_open_source", "vendor": "f5"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[37.0,37.0.2.1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[R36,R36 P6)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "NGINX Plus", "source": "cna", "vendor": "F5"}, "product": "nginx_plus", "vendor": "f5"}], "created": "2026-06-18T19:00:11.430155+00:00", "updated": "2026-06-26T03:30:07.177928+00:00", "vendors": ["f5", "f5$PRODUCT$nginx_open_source", "f5$PRODUCT$nginx_plus"]}