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.
The 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.
One proposed fix for this vulnerability is to patch Decompress.c:887 by breaking if(len <= 0), which has been incorporated in version 3.5.0036 via commit bab062bde40b2ae8a91eecd522e84d8b993bab58.
{
"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"
}{
"versions": [
{
"introduced": "3.5.0001"
},
{
"fixed": "3.5.0036"
}
]
}