{"id":"CVE-2026-88833","state":"PUBLISHED","title":"Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service","description":"A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.","publishedAt":"2026-10-13T16:56:11.068Z","updatedAt":"2026-10-16T22:22:10.834Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"redhat"},"assigner":"redhat","products":["Red Hat Red Hat Hardened Images"],"affected":[{"vendor":"Red Hat","product":"Red Hat Hardened Images","packageName":"busybox","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:hummingbird:1"]}],"references":["https://access.redhat.com/security/cve/CVE-2026-88833","https://bugzilla.redhat.com/show_bug.cgi?id=2531347"],"weaknesses":["CWE-191"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/88xxx/CVE-2026-88833.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-88833","state":"PUBLISHED","datePublished":"2026-10-13T16:56:11.068Z","dateUpdated":"2026-10-16T22:22:10.834Z","assignerShortName":"redhat","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateReserved":"2026-09-10T09:42:04.559Z"},"containers":{"cna":{"title":"Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service","descriptions":[{"lang":"en","value":"A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Hardened Images","packageName":"busybox","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:hummingbird:1"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-88833","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2531347","name":"RHBZ#2531347","tags":["issue-tracking","x_refsource_REDHAT"]}],"metrics":[{"other":{"content":{"value":"Moderate","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-191","description":"Integer Underflow (Wrap or Wraparound)","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"redhat","orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","dateUpdated":"2026-10-13T16:56:11.068Z"},"datePublic":"2026-10-13T13:49:21.595Z","x_redhatCweChain":"CWE-191: Integer Underflow (Wrap or Wraparound)","workarounds":[{"lang":"en","value":"If feasible, use udhcpc in LISTEN_KERNEL mode instead of LISTEN_RAW, or use an alternative DHCP client (dhclient, systemd-networkd). Restrict DHCP traffic on the local segment (for example DHCP snooping on switches)."}],"timeline":[{"lang":"en","time":"2026-09-09T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-10-13T13:49:21.595Z","value":"Made public."}],"credits":[{"lang":"en","value":"Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue."}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-16T22:21:57.578888Z","id":"CVE-2026-88833","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":"2026-10-16T22:22:10.834Z"}}]}}}