{"id":"CVE-2023-31137","summary":"MaraDNS Integer Underflow Vulnerability in DNS Packet Decompression","details":"MaraDNS is open-source software that implements the Domain Name System (DNS). In version 3.5.0024 and prior, a remotely exploitable integer underflow vulnerability in the DNS packet decompression function allows an attacker to cause a Denial of Service by triggering an abnormal program termination.\n\nThe vulnerability exists in the `decomp_get_rddata` function within the `Decompress.c` file. When handling a DNS packet with an Answer RR of qtype 16 (TXT record) and any qclass, if the `rdlength` is smaller than `rdata`, the result of the line `Decompress.c:886` is a negative number `len = rdlength - total;`. This value is then passed to the `decomp_append_bytes` function without proper validation, causing the program to attempt to allocate a massive chunk of memory that is impossible to allocate. Consequently, the program exits with an error code of 64, causing a Denial of Service.\n\nOne proposed fix for this vulnerability is to patch `Decompress.c:887` by breaking `if(len \u003c= 0)`, which has been incorporated in version 3.5.0036 via commit bab062bde40b2ae8a91eecd522e84d8b993bab58.","aliases":["GHSA-58m7-826v-9c3c"],"modified":"2026-08-12T13:34:22.454684Z","published":"2023-05-09T13:56:46.219Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-191"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/31xxx/CVE-2023-31137.json"},"references":[{"type":"WEB","url":"https://github.com/samboy/MaraDNS/blob/08b21ea20d80cedcb74aa8f14979ec7c61846663/dns/Decompress.c#L886"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2023/06/msg00019.html"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3VSMLJX25MXGQ6A7UPOGK7VPUVDESPHL/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NB7LDZM5AGWC5BHHQHW6CP5OFNBBKFOQ/"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/31xxx/CVE-2023-31137.json"},{"type":"ADVISORY","url":"https://github.com/samboy/MaraDNS/security/advisories/GHSA-58m7-826v-9c3c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-31137"},{"type":"ADVISORY","url":"https://www.debian.org/security/2023/dsa-5441"},{"type":"FIX","url":"https://github.com/samboy/MaraDNS/commit/bab062bde40b2ae8a91eecd522e84d8b993bab58"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/samboy/maradns","events":[{"introduced":"d498dc08141791194e4224e3159e0493bd52d447"},{"fixed":"08b21ea20d80cedcb74aa8f14979ec7c61846663"},{"fixed":"bab062bde40b2ae8a91eecd522e84d8b993bab58"}],"database_specific":{"cpe":"cpe:2.3:a:maradns:maradns:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"3.5.0001"},{"fixed":"3.5.0036"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["3.5.0035","3.5.0034","3.5.0033","3.5.0032","3.5.0031","3.5.0030","3.5.0029","3.5.0028","3.5.0027","3.5.0026","coLunacyDNS-1.0.012","3.5.0025","3.5.0024","3.5.0023","3.5.0022","3.5.0021","3.5.0020","3.5.0019","3.5.0018","coLunacyDNS-1.0.010","3.5.0017","coLunacyDNS-1.0.009","3.5.0016","coLunacyDNS-1.0.008","3.5.0015","coLunacyDNS-1.0.002","3.5.0014","3.5.0013","3.5.0012","3.5.0011","3.5.0010","2020-08-06","2020-08-05","2020-08-04","3.5.0009","3.5.0008","3.5.0007","3.5.0006","3.5.0005","3.5.0004","3.5.0003","3.5.0002","3.5.0001"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-31137.json","vanir_signatures_modified":"2026-08-12T13:34:22Z","vanir_signatures":[{"deprecated":false,"digest":{"line_hashes":["89808788349867344767143701345458512602","241827842363765108904724055662740013629","255736606527912446993222367031908925422","307303093863694106346912529890378534176","52455824566973544570874473506454173645"],"threshold":0.9},"id":"CVE-2023-31137-0ffcada4","signature_type":"Line","signature_version":"v1","source":"https://github.com/samboy/maradns/commit/bab062bde40b2ae8a91eecd522e84d8b993bab58","target":{"file":"dns/Decompress.c"}},{"signature_type":"Function","signature_version":"v1","source":"https://github.com/samboy/maradns/commit/bab062bde40b2ae8a91eecd522e84d8b993bab58","target":{"file":"dns/Decompress.c","function":"decomp_get_rddata"},"deprecated":false,"digest":{"function_hash":"23476427869030079362297228092599425269","length":1295},"id":"CVE-2023-31137-e85a946c"}]}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}