{"id":"CVE-2026-56113","state":"PUBLISHED","title":"dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW","description":"dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached.","publishedAt":"2026-06-23T16:05:59.768Z","updatedAt":"2026-07-28T01:49:41.785Z","severity":{"score":6,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["NetworkConfiguration dhcpcd"],"affected":[{"vendor":"NetworkConfiguration","product":"dhcpcd","packageURL":"pkg:github/NetworkConfiguration/dhcpcd","defaultStatus":"affected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.3.2","versionType":"semver"},{"version":"5733d3c59a5651f64357ac11c98b4f39895c8d25","status":"unaffected","versionType":"git"}],"repo":"https://github.com/NetworkConfiguration/dhcpcd"}],"references":["https://github.com/NetworkConfiguration/dhcpcd/commit/5733d3c59a5651f64357ac11c98b4f39895c8d25","https://www.vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56113.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56113","state":"PUBLISHED","datePublished":"2026-06-23T16:05:59.768Z","dateUpdated":"2026-07-28T01:49:41.785Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-06-18T19:15:10.650Z"},"containers":{"cna":{"title":"dhcpcd Heap Use-After-Free in dhcp6_deprecateaddrs via DHCPv6 RENEW","descriptions":[{"lang":"en","value":"dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached."}],"affected":[{"vendor":"NetworkConfiguration","product":"dhcpcd","packageURL":"pkg:github/NetworkConfiguration/dhcpcd","defaultStatus":"affected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.3.2","versionType":"semver"},{"version":"5733d3c59a5651f64357ac11c98b4f39895c8d25","status":"unaffected","versionType":"git"}],"repo":"https://github.com/NetworkConfiguration/dhcpcd"}],"references":[{"url":"https://github.com/NetworkConfiguration/dhcpcd/commit/5733d3c59a5651f64357ac11c98b4f39895c8d25","tags":["patch"]},{"url":"https://www.vulncheck.com/advisories/dhcpcd-heap-use-after-free-in-dhcp6-deprecateaddrs-via-dhcpv6-renew","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"ADJACENT","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"MEDIUM","baseScore":6,"vectorString":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"attackVector":"ADJACENT_NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","version":"3.1","baseSeverity":"MEDIUM","baseScore":5.3,"vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","description":"Use After Free","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-07-28T01:49:41.785Z"},"tags":["x_open-source"],"datePublic":"2026-06-22T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:dhcpcd_project:dhcpcd:*:*:*:*:*:*:*:*","versionEndIncluding":"10.3.2"}]}]}],"credits":[{"lang":"en","value":"CuB3y0nd","type":"finder"},{"lang":"en","value":"VulnCheck","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"vulncheck"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-23T17:58:06.379364Z","id":"CVE-2026-56113","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":"2026-06-23T17:58:21.174Z"}}]}}}