How severe is CVE-2023-28356?

CVE-2023-28356 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-28356 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-28356?

CVE-2023-28356 affects Rocket.chat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-28356?

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

When was CVE-2023-28356 published?

CVE-2023-28356 was published on 2023-05-11 and last updated on 2026-06-17.

CVE-2023-28356

CVE-2023-28356 is a high-severity vulnerability in Rocket.chat with a CVSS 3.x base score of 7.5. 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-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Rocket.chat
Published: 2023-05-11
Last modified: 2026-06-17

Description

A vulnerability has been identified where a maliciously crafted message containing a specific chain of characters can cause the chat to enter a hot loop on one of the processes, consuming ~120% CPU and rendering the service unresponsive.

Frequently asked questions

What is CVE-2023-28356?: A vulnerability has been identified where a maliciously crafted message containing a specific chain of characters can cause the chat to enter a hot loop on one of the processes, consuming ~120% CPU and rendering the service unresponsive.
How severe is CVE-2023-28356?: CVE-2023-28356 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-28356 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-28356?: CVE-2023-28356 affects Rocket.chat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-28356?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-28356 published?: CVE-2023-28356 was published on 2023-05-11 and last updated on 2026-06-17.

References

https://hackerone.com/reports/1461340

Affected products (1)

cpe:2.3:a:rocket.chat:rocket.chat:*:*:*:*:*:*:*:*

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