CVE-2001-0170: glibc 2.1.9x and earlier does not properly clear the RESOLV_HOST_CONF, HOSTALIASES, or RES_OPTIONS environment

Routine

LOW 2.1WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2001-0170 is a low-severity flaw (CVSS 2.1) affecting immunix, linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

glibc 2.1.9x and earlier does not properly clear the RESOLV_HOST_CONF, HOSTALIASES, or RES_OPTIONS environmental variables when executing setuid/setgid programs, which could allow local users to read arbitrary files.

Why this priority

Public exploit reference
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	2.1 (Low)
EPSS exploit chance	0.8% (top 42%)
CISA exploited list	No
Published	2001-03-26
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: conectiva · debian · immunix · redhat

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2001-03-26 05:00 UTCPublished CVE record published
2026-06-16 21:53 UTCUpdated Record last modified

immunix immunix DOWNGRADE

Affected: 7.0_beta

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0_beta

1. Check installed version

apt-cache policy immunix || rpm -q immunix || immunix --version

2. No fixed release: DOWNGRADE to a release before 7.0_beta (Debian / Ubuntu)

apt-cache madison immunix sudo apt install immunix=<VERSION_BEFORE_7.0_beta> sudo apt-mark hold immunix

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list immunix sudo dnf downgrade immunix-<VERSION_BEFORE_7.0_beta> sudo dnf versionlock add immunix

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.

conectiva linux MITIGATE

Affected: 4.0 · 4.0es · 4.1 · 4.2 · 5.0 · 5.1 · 6.0 · ecommerce

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 2.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat linux MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: glibc-2.2 / openssh-2.3.0p1 / glibc 2.1.9x - File Read
Exploit-DB: Resolv+ 'RESOLV_HOST_CONF' - Linux Library Command Execution

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-2001-0170?

immunix: downgrade or apply the listed mitigation; linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2001-0170 being exploited?

CVE-2001-0170 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-2001-0170 affect?

CVE-2001-0170 affects immunix, linux, debian linux. Severity is low (CVSS 2.1). glibc 2.1.9x and earlier does not properly clear the RESOLV_HOST_CONF, HOSTALIASES, or RES_OPTIONS environmental variables when executing setuid/setgid programs, which could allow local users to read arbitrary files.

How urgent is CVE-2001-0170?

Priority 32/100. Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities · glibc vulnerabilities

Related CVEs

CVE-2000-0963 HIGH 7.2 DOWNGRADE MITIGATE Buffer overflow in ncurses library allows local users to execute arbitrary commands via long environmental inf
CVE-2002-1565 HIGH 7.5 DOWNGRADE Buffer overflow in url_filename function for wget 1.8.1 allows attackers to cause a denial of service (segment
CVE-2002-0083 CRITICAL 9.8 DOWNGRADE DOWNGRADE Off-by-one error in the channel code of OpenSSH 2.0 through 3.0.2 allows local users or remote malicious serve
CVE-2001-1030 HIGH 7.5 DOWNGRADE DOWNGRADE Squid before 2.3STABLE5 in HTTP accelerator mode does not enable access control lists (ACLs) when the httpd_ac
CVE-2001-0738 MEDIUM 5.0 DOWNGRADE MITIGATE LogLine function in klogd in sysklogd 1.3 in various Linux distributions allows an attacker to cause a denial

References

← Back to latest CVEs