CVE-2020-35857 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in trust-dns-server. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for trust-dns-server — see the affected versions and patch details below.
Stack consumption in trust-dns-server
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
trust-dns-serverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
There's a stack overflow leading to a crash and potential DOS when processing additional records for return of MX or SRV record types from the server. This is only possible when a zone is configured with a null target for MX or SRV records. Prior to 0.16.0 the additional record processing was not supported by trust-dns-server. There Are no known issues with upgrading from 0.16 or 0.17 to 0.18.1. The remidy should be to upgrade to 0.18.1. If unable to do so, MX, SRV or other record types with a target to the null type, should be avoided.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | trust-dns-server | ≥ 0.16.0&&< 0.18.1 | 0.18.1cargo update -p trust-dns-server --precise 0.18.1 |
Affected Products
trust-dns-servertrust-dns-server_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for trust-dns-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update trust-dns-server to 0.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-35857 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Frequently Asked Questions
Is CVE-2020-35857 in your dependencies?
Find it across crates.io, including transitive dependencies.