CVE-2020-10857: Zulip Desktop before 5.0.0 improperly uses shell.openExternal and shell.openItem with untrusted content, leadi

Q: How do I fix CVE-2020-10857?

zulip desktop: upgrade to 5.0.0. Exact commands for each OS are on this page.

Q: Is CVE-2020-10857 being exploited?

CVE-2020-10857 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-10857 affect?

CVE-2020-10857 affects zulip desktop. Severity is critical (CVSS 9.8). Zulip Desktop before 5.0.0 improperly uses shell.openExternal and shell.openItem with untrusted content, leading to remote code execution.

Q: How urgent is CVE-2020-10857?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2020-10857 is a critical-severity flaw (CVSS 9.8) affecting zulip desktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zulip Desktop before 5.0.0 improperly uses shell.openExternal and shell.openItem with untrusted content, leading to remote code execution.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.0% (top 13%)
CISA exploited list	No
Published	2021-02-05
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zulip

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

Am I affected?

Timeline

2021-02-05 20:15 UTCPublished CVE record published
2026-06-17 02:48 UTCUpdated Record last modified

zulip zulip desktop UPGRADE

Affected: < 5.0.0

Fixed in: 5.0.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy zulip-desktop || rpm -q zulip-desktop || zulip-desktop --version

2. UPGRADE to 5.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zulip-desktop

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zulip-desktop

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2020-10857?

zulip desktop: upgrade to 5.0.0. Exact commands for each OS are on this page.

Is CVE-2020-10857 being exploited?

CVE-2020-10857 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-2020-10857 affect?

CVE-2020-10857 affects zulip desktop. Severity is critical (CVSS 9.8). Zulip Desktop before 5.0.0 improperly uses shell.openExternal and shell.openItem with untrusted content, leading to remote code execution.

How urgent is CVE-2020-10857?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-9443 MEDIUM 6.1 UPGRADE Zulip Desktop before 4.0.3 loaded untrusted content in an Electron webview with web security disabled, which c
CVE-2020-24582 MEDIUM 6.1 UPGRADE Zulip Desktop before 5.4.3 allows XSS because string escaping is mishandled during composition of the HTML for
CVE-2020-12637 CRITICAL 9.8 UPGRADE Zulip Desktop before 5.2.0 has Missing SSL Certificate Validation because all validation was inadvertently dis
CVE-2020-10858 MEDIUM 5.3 UPGRADE Zulip Desktop before 5.0.0 allows attackers to perform recording via the webcam and microphone due to a missin

References

← Back to latest CVEs