{"id":"CVE-2026-6554","state":"PUBLISHED","title":"infinte loop in libpcap before 1.10.7","description":"libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations.  A crafted filter program or the 'protochain' primitive used on a crafted network packet can cause the interpreter to loop infinitely.","publishedAt":"2026-09-05T18:51:02.338Z","updatedAt":"2026-10-22T20:08:13.106Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Tcpdump"},"assigner":"Tcpdump","products":["The Tcpdump Group libpcap"],"affected":[{"vendor":"The Tcpdump Group","product":"libpcap","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.10.7","versionType":"semver"}],"modules":["BPF interpreter"],"programFiles":["bpf_filter.c"],"programRoutines":[{"name":"pcapint_filter_with_aux_data()"}],"repo":"https://github.com/the-tcpdump-group/libpcap/"}],"references":["https://github.com/the-tcpdump-group/libpcap/commit/ff3c83475ac303c6b681c52ad0b6e14795a8e0ce","http://www.openwall.com/lists/oss-security/2026/10/22/3"],"weaknesses":["CWE-835"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/6xxx/CVE-2026-6554.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6554","state":"PUBLISHED","datePublished":"2026-09-05T18:51:02.338Z","dateUpdated":"2026-10-22T20:08:13.106Z","assignerShortName":"Tcpdump","assignerOrgId":"cfdbb673-b408-4d03-89c1-c3d73ed80896","dateReserved":"2026-04-17T22:00:24.313Z"},"containers":{"cna":{"title":"infinte loop in libpcap before 1.10.7","descriptions":[{"lang":"en","value":"libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations.  A crafted filter program or the 'protochain' primitive used on a crafted network packet can cause the interpreter to loop infinitely."}],"affected":[{"vendor":"The Tcpdump Group","product":"libpcap","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.10.7","versionType":"semver"}],"modules":["BPF interpreter"],"programFiles":["bpf_filter.c"],"programRoutines":[{"name":"pcapint_filter_with_aux_data()"}],"repo":"https://github.com/the-tcpdump-group/libpcap/"}],"references":[{"url":"https://github.com/the-tcpdump-group/libpcap/commit/ff3c83475ac303c6b681c52ad0b6e14795a8e0ce","tags":["patch"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-835","description":"CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"Tcpdump","orgId":"cfdbb673-b408-4d03-89c1-c3d73ed80896","dateUpdated":"2026-10-22T17:28:27.086Z"},"configurations":[{"lang":"en","value":"An uncommon vulnerable configuration is an application that uses pcap_offline_filter() or bpf_filter() with an externally-supplied compiled filter program without validating the program first."},{"lang":"en","value":"A common vulnerable configuration is an application that uses pcap_compile() to compile a filter expression, but the expression uses the 'protochain' primitive.  Support for this primitive is conditional, but is enabled by default."}],"credits":[{"lang":"en","type":"reporter","value":"Kaixuan LI has discovered the crafted filter program attack vector"},{"lang":"en","type":"finder","value":"Denis Ovsienko has discovered the 'protochain' attack vector"}],"exploits":[{"lang":"en","value":"Functional exploits exist for both attack vectors."}],"solutions":[{"lang":"en","value":"Upgrade to libpcap 1.10.7."}],"source":{"discovery":"UNKNOWN"},"workarounds":[{"lang":"en","value":"Do not use filter programs that have been compiled outside of libpcap.  Build libpcap without the 'protochain' primitive support."}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T15:14:56.820512Z","id":"CVE-2026-6554","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":"2026-09-08T15:15:06.137Z"}},{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/10/22/3"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-10-22T20:08:13.106Z"}}]}}}