How severe is CVE-2021-35299?

CVE-2021-35299 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 high, integrity none, and availability none.

Is CVE-2021-35299 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-35299?

CVE-2021-35299 affects Zammad. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-35299?

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-2021-35299 published?

CVE-2021-35299 was published on 2021-06-28 and last updated on 2026-06-17.

CVE-2021-35299

CVE-2021-35299 is a high-severity vulnerability in Zammad 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-532.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-532
Affected product: Zammad
Published: 2021-06-28
Last modified: 2026-06-17

Description

Incorrect Access Control in Zammad 1.0.x up to 4.0.0 allows attackers to obtain sensitive information via email connection configuration probing.

Frequently asked questions

What is CVE-2021-35299?: Incorrect Access Control in Zammad 1.0.x up to 4.0.0 allows attackers to obtain sensitive information via email connection configuration probing.
How severe is CVE-2021-35299?: CVE-2021-35299 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 high, integrity none, and availability none.
Is CVE-2021-35299 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35299?: CVE-2021-35299 affects Zammad. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35299?: 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-2021-35299 published?: CVE-2021-35299 was published on 2021-06-28 and last updated on 2026-06-17.

References

https://zammad.com/en/advisories/zaa-2021-02

Affected products (1)

cpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:*

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