CVE-2020-9443: Zulip Desktop before 4.0.3 loaded untrusted content in an Electron webview with web security disabled, which c

Q: How do I fix CVE-2020-9443?

zulip desktop: upgrade to 4.0.3. Exact commands for each OS are on this page.

Q: Is CVE-2020-9443 being exploited?

CVE-2020-9443 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-2020-9443 affect?

CVE-2020-9443 affects zulip desktop. Severity is medium (CVSS 6.1). Zulip Desktop before 4.0.3 loaded untrusted content in an Electron webview with web security disabled, which can be exploited for XSS in a number of ways. This especially affects Zulip Desktop 2.3.82.

Q: How urgent is CVE-2020-9443?

Priority 34/100. No elevated risk signals yet.

Routine

MEDIUM 6.1UPGRADE

CVE-2020-9443 is a medium-severity flaw (CVSS 6.1) affecting zulip desktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zulip Desktop before 4.0.3 loaded untrusted content in an Electron webview with web security disabled, which can be exploited for XSS in a number of ways. This especially affects Zulip Desktop 2.3.82.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-03-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zulipchat

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

Am I affected?

Timeline

2020-03-18 13:15 UTCPublished CVE record published
2026-06-17 03:27 UTCUpdated Record last modified

zulipchat zulip desktop UPGRADE

Affected: < 4.0.3

Fixed in: 4.0.3

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 4.0.3 (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-2020-9443?

zulip desktop: upgrade to 4.0.3. Exact commands for each OS are on this page.

Is CVE-2020-9443 being exploited?

CVE-2020-9443 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-2020-9443 affect?

CVE-2020-9443 affects zulip desktop. Severity is medium (CVSS 6.1). Zulip Desktop before 4.0.3 loaded untrusted content in an Electron webview with web security disabled, which can be exploited for XSS in a number of ways. This especially affects Zulip Desktop 2.3.82.

How urgent is CVE-2020-9443?

Priority 34/100. No elevated risk signals yet.

Software pages

Electron vulnerabilities

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References

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