CVE-2020-35857: An issue was discovered in the trust-dns-server crate before 0.18.1 for Rust

This week

HIGH 7.5REMOTEUPGRADE

CVE-2020-35857 is a high-severity flaw (CVSS 7.5) affecting trust-dns-server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in the trust-dns-server crate before 0.18.1 for Rust. DNS MX and SRV null targets are mishandled, causing stack consumption.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 27%)
CISA exploited list	No
Weakness	CWE-400
Published	2020-12-31
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: trust-dns-server project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-12-31 10:15 UTCPublished CVE record published
2026-06-17 03:14 UTCUpdated Record last modified

trust-dns-server project trust-dns-server UPGRADE

Affected: >= 0.16.0 and < 0.18.1

Fixed in: 0.18.1

Safe to downgrade to: a release before 0.16.0

1. Check installed version

apt-cache policy trust-dns-server || rpm -q trust-dns-server || trust-dns-server --version

2. UPGRADE to 0.18.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade trust-dns-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade trust-dns-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.16.0 (Debian / Ubuntu)

apt-cache madison trust-dns-server sudo apt install trust-dns-server=<VERSION_BEFORE_0.16.0> sudo apt-mark hold trust-dns-server

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list trust-dns-server sudo dnf downgrade trust-dns-server-<VERSION_BEFORE_0.16.0> sudo dnf versionlock add trust-dns-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-35857?

trust-dns-server: upgrade to 0.18.1. Exact commands for each OS are on this page.

Is CVE-2020-35857 being exploited?

CVE-2020-35857 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-35857 affect?

CVE-2020-35857 affects trust-dns-server. Severity is high (CVSS 7.5). An issue was discovered in the trust-dns-server crate before 0.18.1 for Rust. DNS MX and SRV null targets are mishandled, causing stack consumption.

How urgent is CVE-2020-35857?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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