How severe is CVE-2020-10857?

CVE-2020-10857 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-10857 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10857?

CVE-2020-10857 affects Zulip Zulip Desktop. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-10857?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-10857 published?

CVE-2020-10857 was published on 2021-02-05 and last updated on 2026-06-17.

CVE-2020-10857

CVE-2020-10857 is a critical-severity vulnerability in Zulip Zulip Desktop with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Zulip Zulip Desktop
Published: 2021-02-05
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2020-10857?: Zulip Desktop before 5.0.0 improperly uses shell.openExternal and shell.openItem with untrusted content, leading to remote code execution.
How severe is CVE-2020-10857?: CVE-2020-10857 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-10857 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-10857?: CVE-2020-10857 affects Zulip Zulip Desktop. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-10857?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-10857 published?: CVE-2020-10857 was published on 2021-02-05 and last updated on 2026-06-17.

References

https://blog.zulip.com/2020/04/01/zulip-desktop-5-0-0-security-release/

Affected products (1)

cpe:2.3:a:zulip:zulip_desktop:*:*:*:*:*:*:*:*

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