How severe is CVE-2023-26433?

CVE-2023-26433 has a CVSS 3.x base score of 4.3, 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 low.

Is CVE-2023-26433 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-26433?

CVE-2023-26433 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-2023-26433?

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

When was CVE-2023-26433 published?

CVE-2023-26433 was published on 2023-06-20 and last updated on 2026-06-17.

CVE-2023-26433

CVE-2023-26433 is a medium-severity vulnerability in Open-xchange Open-xchange Appsuite Backend with a CVSS 3.x base score of 4.3. 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: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Open-xchange Open-xchange Appsuite Backend
Published: 2023-06-20
Last modified: 2026-06-17

Description

When adding an external mail account, processing of IMAP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue IMAP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted IMAP server response to reasonable length/size. No publicly available exploits are known.

Frequently asked questions

What is CVE-2023-26433?: When adding an external mail account, processing of IMAP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue IMAP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted IMAP server response to reasonable length/size. No publicly available exploits are known.
How severe is CVE-2023-26433?: CVE-2023-26433 has a CVSS 3.x base score of 4.3, 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 low.
Is CVE-2023-26433 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-26433?: CVE-2023-26433 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-2023-26433?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-26433 published?: CVE-2023-26433 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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