CVE-2020-23891: A User Mode Write AV in Editor+0x5cd7 of WildBit Viewer v6.6 allows attackers to cause a denial of service (Do

Routine

MEDIUM 5.5DOWNGRADE

CVE-2020-23891 is a medium-severity flaw (CVSS 5.5) affecting wildbit viewer. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A User Mode Write AV in Editor+0x5cd7 of WildBit Viewer v6.6 allows attackers to cause a denial of service (DoS) via a crafted tiff file.

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	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-787
Published	2021-11-10
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: wildbit-soft

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

Am I affected?

Timeline

2021-11-10 22:15 UTCPublished CVE record published
2026-06-17 03:05 UTCUpdated Record last modified

wildbit-soft wildbit viewer DOWNGRADE

Affected: 6.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.6

1. Check installed version

apt-cache policy wildbit-viewer || rpm -q wildbit-viewer || wildbit-viewer --version

2. No fixed release: DOWNGRADE to a release before 6.6 (Debian / Ubuntu)

apt-cache madison wildbit-viewer sudo apt install wildbit-viewer=<VERSION_BEFORE_6.6> sudo apt-mark hold wildbit-viewer

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

dnf --showduplicates list wildbit-viewer sudo dnf downgrade wildbit-viewer-<VERSION_BEFORE_6.6> sudo dnf versionlock add wildbit-viewer

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-2020-23891?

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

Is CVE-2020-23891 being exploited?

CVE-2020-23891 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-2020-23891 affect?

CVE-2020-23891 affects wildbit viewer. Severity is medium (CVSS 5.5). A User Mode Write AV in Editor+0x5cd7 of WildBit Viewer v6.6 allows attackers to cause a denial of service (DoS) via a crafted tiff file.

How urgent is CVE-2020-23891?

Priority 37/100. Public exploit reference

Related CVEs

CVE-2020-23902 MEDIUM 5.5 DOWNGRADE A buffer overflow in WildBit Viewer v6.6 allows attackers to cause a denial of service (DoS) via a crafted tga
CVE-2020-23901 MEDIUM 5.5 DOWNGRADE A User Mode Write AV in Editor+0x5d15 of WildBit Viewer v6.6 allows attackers to cause a denial of service (Do
CVE-2020-23900 MEDIUM 5.5 DOWNGRADE A buffer overflow in WildBit Viewer v6.6 allows attackers to cause a denial of service (DoS) via a crafted tga
CVE-2020-23899 MEDIUM 5.5 DOWNGRADE A User Mode Write AV in Editor+0x5f91 of WildBit Viewer v6.6 allows attackers to cause a denial of service (Do
CVE-2020-23898 MEDIUM 5.5 DOWNGRADE A User Mode Write AV in Editor+0x5ea2 of WildBit Viewer v6.6 allows attackers to cause a denial of service (Do

References

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