CVE-2018-1000034: An out-of-bounds read exists in Info-Zip UnZip version 6.10c22 that allows an attacker to perform a denial of

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CRITICAL 9.1REMOTEDOWNGRADE

CVE-2018-1000034 is a critical-severity flaw (CVSS 9.1) affecting unzip. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An out-of-bounds read exists in Info-Zip UnZip version 6.10c22 that allows an attacker to perform a denial of service and read sensitive memory.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-125
Published	2018-02-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: info-zip

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

Am I affected?

Timeline

2018-02-09 23:29 UTCPublished CVE record published
2026-06-17 01:32 UTCUpdated Record last modified

info-zip unzip DOWNGRADE

Affected: 6.10c22

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.10c22

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 6.10c22 (Debian / Ubuntu)

apt-cache madison unzip sudo apt install unzip=<VERSION_BEFORE_6.10c22> sudo apt-mark hold unzip

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

dnf --showduplicates list unzip sudo dnf downgrade unzip-<VERSION_BEFORE_6.10c22> sudo dnf versionlock add unzip

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-2018-1000034?

unzip: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-1000034 being exploited?

CVE-2018-1000034 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-2018-1000034 affect?

CVE-2018-1000034 affects unzip. Severity is critical (CVSS 9.1). An out-of-bounds read exists in Info-Zip UnZip version 6.10c22 that allows an attacker to perform a denial of service and read sensitive memory.

How urgent is CVE-2018-1000034?

Priority 55/100. Critical severity; Remotely exploitable, no login, no user action

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References

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