CVE-2020-18770: An issue was discovered in function zzip_disk_entry_to_file_header in mmapped.c in zziplib 0.13.69, which will

Routine

MEDIUM 5.5DOWNGRADE

CVE-2020-18770 is a medium-severity flaw (CVSS 5.5) affecting zziplib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in function zzip_disk_entry_to_file_header in mmapped.c in zziplib 0.13.69, which will lead to a denial-of-service.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-400
Published	2023-08-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: gdraheim

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

Am I affected?

Timeline

2023-08-22 19:15 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.

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-2020-18770?

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

Is CVE-2020-18770 being exploited?

CVE-2020-18770 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-2020-18770 affect?

CVE-2020-18770 affects zziplib. Severity is medium (CVSS 5.5). An issue was discovered in function zzip_disk_entry_to_file_header in mmapped.c in zziplib 0.13.69, which will lead to a denial-of-service.

How urgent is CVE-2020-18770?

Priority 31/100. Public exploit reference

Related CVEs

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 _

References

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