{"id":"CVE-2026-19538","state":"PUBLISHED","title":"Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS","description":"The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open.","publishedAt":"2026-08-26T08:47:08.992Z","updatedAt":"2026-08-26T14:00:12.918Z","severity":{"score":8.2,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"NLnet Labs"},"assigner":"NLnet Labs","products":["NLnet Labs NSD"],"affected":[{"vendor":"NLnet Labs","product":"NSD","defaultStatus":"unaffected","versions":[{"version":"4.8.0","status":"affected","lessThan":"4.15.1","versionType":"semver"}]}],"references":["https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19538.txt"],"weaknesses":["CWE-290","CWE-672"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/19xxx/CVE-2026-19538.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-19538","state":"PUBLISHED","datePublished":"2026-08-26T08:47:08.992Z","dateUpdated":"2026-08-26T14:00:12.918Z","assignerShortName":"NLnet Labs","assignerOrgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","dateReserved":"2026-08-11T10:27:22.294Z"},"containers":{"cna":{"title":"Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS","descriptions":[{"lang":"en","value":"The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open."}],"affected":[{"vendor":"NLnet Labs","product":"NSD","defaultStatus":"unaffected","versions":[{"version":"4.8.0","status":"affected","lessThan":"4.15.1","versionType":"semver"}]}],"references":[{"url":"https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19538.txt","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"Explicitly denied access to the proxy protocol port is bypassed on TCP or TLS"}],"cvssV4_0":{"version":"4.0","baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-290","lang":"en","description":"CWE-290 Authentication Bypass by Spoofing","type":"CWE"},{"cweId":"CWE-672","lang":"en","description":"CWE-672 Operation on a Resource after Expiration or Release","type":"CWE"}]}],"providerMetadata":{"shortName":"NLnet Labs","orgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","dateUpdated":"2026-08-26T08:47:08.992Z"},"solutions":[{"lang":"en","value":"This issue is fixed in 4.15.1 and all later versions."}],"credits":[{"lang":"en","type":"finder","value":"Qifan Zhang from Palo Alto Networks"}],"timeline":[{"time":"2026-07-15T18:04:25.000Z","lang":"en","value":"Issue reported by Qifan Zhang"},{"time":"2026-08-10T07:56:32.000Z","lang":"en","value":"NLnet Labs shares patch"},{"time":"2026-08-15T00:00:00.000Z","lang":"en","value":"Qifan Zhang verifies patch"},{"time":"2026-08-26T12:00:00.000Z","lang":"en","value":"Fix released with version 4.15.1"}],"datePublic":"2026-08-26T12:00:00.000Z","x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-26T13:51:21.490331Z","id":"CVE-2026-19538","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-26T14:00:12.918Z"}}]}}}