How severe is CVE-2019-16215?

CVE-2019-16215 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-16215 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-16215?

CVE-2019-16215 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-16215?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-16215 published?

CVE-2019-16215 was published on 2019-09-18 and last updated on 2026-06-17.

CVE-2019-16215

CVE-2019-16215 is a medium-severity vulnerability in Zulip Zulip Server with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Zulip Zulip Server
Published: 2019-09-18
Last modified: 2026-06-17

Description

The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.

Frequently asked questions

What is CVE-2019-16215?: The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.
How severe is CVE-2019-16215?: CVE-2019-16215 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-16215 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-16215?: CVE-2019-16215 affects Zulip Zulip Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-16215?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-16215 published?: CVE-2019-16215 was published on 2019-09-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*

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