CVE-2026-28435

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{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,0.35.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "cpp-httplib", "source": "cna", "vendor": "yhirose"}, "product": "cpp-httplib", "vendor": "yhirose"}], "analysis": {"en": {"generated_at": "2026-04-16T13:08:05.151614+00:00", "value": {"mitigation_remediation": ["Upgrade cpp-httplib to version 0.35.0 or later where the payload size check is enforced after decompression.", "If upgrading is not possible, add application\u2011level enforcement of a strict payload size limit before decompression or reject requests that exceed a safe threshold, especially when Content\u2011Encoding: gzip is present.", "Monitor HTTP traffic for unusually large compressed payloads and apply network\u2011level rate limiting or connection throttling to mitigate memory exhaustion attempts."], "summary": {"action": "Patch", "impact": "Payload size limit bypass leading to denial of service."}, "threat_synthesis": {"affected_systems": "The vulnerability affects the yhirose:cpp-httplib library, specifically versions prior to 0.35.0. The issue arises in the HandlerWithContentReader use case when Server::set_payload_max_length() is not checked after decompression.", "description_and_impact": "cpp-httplib does not enforce the maximum payload length on a decompressed request body when using streaming ContentReader with Content-Encoding gzip. A small compressed payload can therefore expand beyond the configured limit and be processed by the application, allowing a payload size limit bypass. This flaw can consume excessive CPU or memory, resulting in a denial of service and application unavailability.", "risk_and_exploitability": "With a CVSS score of 7.5, the flaw is considered high severity but the EPSS score is below 1%, indicating a low probability of exploitation at the current time and it is not listed in the KEV catalog. The likely attack vector is remote, through an HTTP(S) request that includes a gzip\u2011encoded payload that, when decompressed, exceeds the application\u2019s configured size limit. An attacker can trigger excessive resource consumption and cause a denial of service."}}}}, "created": "2026-03-05T09:05:47.037592+00:00", "updated": "2026-04-16T13:15:06.225040+00:00", "vendors": ["yhirose", "yhirose$PRODUCT$cpp-httplib"]}