{"attribution":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","cve":{"id":"CVE-2026-63075","sourceIdentifier":"openssl-security@openssl.org","published":"2026-08-25T13:19:26.413","lastModified":"2026-09-11T21:17:05.403","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly\nsends ack-eliciting packets while not acknowledging ACK-only responses, the\nQUIC stack can retain ACK-only packet metadata for the lifetime of the\nconnection.\n\nImpact summary: A remote peer that can complete a QUIC handshake can\ncause connection-scoped memory growth which may lead to Denial of Service\nthrough memory exhaustion, especially with sustained traffic or many concurrent\nQUIC connections.\n\nCWE: CWE-770: Allocation of Resources Without Limits or Throttling\n\nDescription: When the OpenSSL QUIC stack sends an ACK-only packet,\nthere is no requirement by the QUIC protocol that the peer will acknowledge\nthat ACK-only packet (i.e. it is itself not ack-eliciting). However, the OpenSSL\nimplementation stores the metadata about the ACK frames regardless.\nIn and of itself that's ok, but if a malicious peer establishes a connection, and\nthen drives the connection such that ACK-only packets are forced from the \nOpenSSL implementation peer (i.e., by sending numerous PING frames),\nand then withholding any subsequent acks for ack-eliciting data, like\nlegitimate data, said malicious peer can force inappropriate memory growth\non the OpenSSL peer, potentially leading to a Denial of Service.\n\nThe fix is to ensure that we account for the transmission of the ACK-only\npacket in the packet histories high and low watermark without actually storing\nthe ACK-only packet metadata itself.\n\nFIPS impact: no\nThe OpenSSL FIPS module is not affected as the QUIC code is\noutside the FIPS module boundary."}],"affected":[{"source":"openssl-security@openssl.org","affectedData":[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","lessThan":"4.0.2","versionType":"semver","status":"affected"},{"version":"3.6.0","lessThan":"3.6.4","versionType":"semver","status":"affected"},{"version":"3.5.0","lessThan":"3.5.8","versionType":"semver","status":"affected"},{"version":"3.4.0","lessThan":"3.4.7","versionType":"semver","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-25T14:36:48.832724Z","id":"CVE-2026-63075","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"openssl-security@openssl.org","type":"Secondary","description":[{"lang":"en","value":"CWE-770"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4.0","versionEndExcluding":"3.4.7","matchCriteriaId":"216D6529-561A-4684-A886-50954FBEBFB2"},{"vulnerable":true,"criteria":"cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5.0","versionEndExcluding":"3.5.8","matchCriteriaId":"C5BB9E95-09B6-4163-B51C-D62B528A04DA"},{"vulnerable":true,"criteria":"cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6.0","versionEndExcluding":"3.6.4","matchCriteriaId":"B1416826-F2F1-4EA8-9FB2-A56B0DA923C1"},{"vulnerable":true,"criteria":"cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0.0","versionEndExcluding":"4.0.2","matchCriteriaId":"63B8F45B-E44F-481C-815D-AF9CA89C48F6"}]}]}],"references":[{"url":"https://github.com/openssl/openssl/commit/7308946576b12e64b8be53bcf0a120354b2b42bc","source":"openssl-security@openssl.org","tags":["Patch"]},{"url":"https://github.com/openssl/openssl/commit/7c98d79738549df92868e7dd9be4bbf061eed709","source":"openssl-security@openssl.org","tags":["Patch"]},{"url":"https://github.com/openssl/openssl/commit/bf84721c2548351176e367e6de505792f0118dc6","source":"openssl-security@openssl.org","tags":["Patch"]},{"url":"https://github.com/openssl/openssl/commit/c902e5f16d6a9e130e96d3ca6d8f64d71652e393","source":"openssl-security@openssl.org","tags":["Patch"]},{"url":"https://openssl-library.org/news/secadv/20260825.txt","source":"openssl-security@openssl.org","tags":["Vendor Advisory"]}]}}