CVE-2020-18442: Infinite Loop in zziplib v0.13.69 allows remote attackers to cause a denial of service via the return value "z

Routine

LOW 3.3WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2020-18442 is a low-severity flaw (CVSS 3.3) affecting zziplib, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Infinite Loop in zziplib v0.13.69 allows remote attackers to cause a denial of service via the return value "zzip_file_read" in the function "unzzip_cat_file".

Why this priority

Public exploit reference
On your watchlist

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

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.7% (top 45%)
CISA exploited list	No
Weakness	CWE-835
Published	2021-06-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · fedoraproject · gdraheim

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

Am I affected?

Timeline

2021-06-18 15:15 UTCPublished CVE record published
2026-06-17 02:59 UTCUpdated Record last modified

gdraheim zziplib DOWNGRADE

Affected: 0.13.69

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.13.69

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.13.69 (Debian / Ubuntu)

apt-cache madison zziplib sudo apt install zziplib=<VERSION_BEFORE_0.13.69> sudo apt-mark hold zziplib

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

dnf --showduplicates list zziplib sudo dnf downgrade zziplib-<VERSION_BEFORE_0.13.69> sudo dnf versionlock add zziplib

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.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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.

fedoraproject fedora MITIGATE

Affected: 34 · 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

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.

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-2020-18442?

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

Is CVE-2020-18442 being exploited?

CVE-2020-18442 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-2020-18442 affect?

CVE-2020-18442 affects zziplib, debian linux, fedora. Severity is low (CVSS 3.3). Infinite Loop in zziplib v0.13.69 allows remote attackers to cause a denial of service via the return value "zzip_file_read" in the function "unzzip_cat_file".

How urgent is CVE-2020-18442?

Priority 35/100. Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2018-17828 MEDIUM 5.5 DOWNGRADE Directory traversal vulnerability in ZZIPlib 0.13.69 allows attackers to overwrite arbitrary files via a .
CVE-2024-39134 HIGH 7.5 DOWNGRADE A Stack Buffer Overflow vulnerability in zziplibv 0.13.77 allows attackers to cause a denial of service via th
CVE-2024-39133 MEDIUM 4.3 DOWNGRADE Heap Buffer Overflow vulnerability in zziplib v0.13.77 allows attackers to cause a denial of service via the _
CVE-2020-18770 MEDIUM 5.5 DOWNGRADE An issue was discovered in function zzip_disk_entry_to_file_header in mmapped.c in zziplib 0.13.69, which will
CVE-2018-7727 MEDIUM 6.5 DOWNGRADE MITIGATE An issue was discovered in ZZIPlib 0.13.68

References

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