How severe is CVE-2023-26428?

CVE-2023-26428 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 high, integrity none, and availability none.

Is CVE-2023-26428 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-26428?

CVE-2023-26428 primarily affects Open-xchange Open-xchange Appsuite Backend. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-26428?

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

When was CVE-2023-26428 published?

CVE-2023-26428 was published on 2023-06-20 and last updated on 2026-06-17.

CVE-2023-26428

CVE-2023-26428 is a medium-severity vulnerability in Open-xchange Open-xchange Appsuite Backend 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-639.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-639
Affected product: Open-xchange Open-xchange Appsuite Backend
Published: 2023-06-20
Last modified: 2026-06-17

Description

Attackers can successfully request arbitrary snippet IDs, including E-Mail signatures of other users within the same context. Signatures of other users could be read even though they are not explicitly shared. We improved permission handling when requesting snippets that are not explicitly shared with other users. No publicly available exploits are known.

Frequently asked questions

What is CVE-2023-26428?: Attackers can successfully request arbitrary snippet IDs, including E-Mail signatures of other users within the same context. Signatures of other users could be read even though they are not explicitly shared. We improved permission handling when requesting snippets that are not explicitly shared with other users. No publicly available exploits are known.
How severe is CVE-2023-26428?: CVE-2023-26428 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 high, integrity none, and availability none.
Is CVE-2023-26428 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-26428?: CVE-2023-26428 primarily affects Open-xchange Open-xchange Appsuite Backend. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-26428?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-26428 published?: CVE-2023-26428 was published on 2023-06-20 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:open-xchange:open-xchange_appsuite_backend:*:*:*:*:*:*:*:*
cpe:2.3:a:open-xchange:open-xchange_appsuite_backend:7.10.6:*:*:*:*:*:*:*
cpe:2.3:a:open-xchange:open-xchange_appsuite_backend:7.10.6:revision_39:*:*:*:*:*:*

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