Integer overflow in Maradns
CVE-2023-31137
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.011 (65.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 65.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000
Affected products
- Maradns
- Samboy Maradns — versions <= 3.5.0024
- Debian Linux — versions 10.0, 11.0
- Fedoraproject Fedora — versions 37, 38
Weakness classification (CWE)
References
- github.com/samboy/MaraDNS/security/advisories/GHSA-58m7-826v-9c3c (Vendor Advisory)
- github.com/samboy/MaraDNS/commit/bab062bde40b2ae8a91eecd522e84d8b993bab58 (Patch)
- github.com/samboy/MaraDNS/blob/08b21ea20d80cedcb74aa8f14979ec7c61846663/dns/Dec… (Product)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2023/06/msg00019.html (Mailing List, Third Party Advisory)
- www.debian.org/security/2023/dsa-5441 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2023-31137?
- CVE-2023-31137 is a high-severity vulnerability in Maradns, classified under Integer Underflow. CVSS score: 7.5/10. Published 2023-05-09.
- How severe is CVE-2023-31137?
- High severity. CVSS v3 base score is 7.5 out of 10.