How severe is CVE-2023-26430?

CVE-2023-26430 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2023-26430 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-26430?

CVE-2023-26430 primarily affects Open-xchange Open-xchange Appsuite Backend. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-26430?

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

When was CVE-2023-26430 published?

CVE-2023-26430 was published on 2023-08-02 and last updated on 2026-06-17.

CVE-2023-26430

CVE-2023-26430 is a low-severity vulnerability in Open-xchange Open-xchange Appsuite Backend with a CVSS 3.x base score of 3.5. 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-77.

Key facts

Severity: Low (CVSS 3.x base score 3.5)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-77
Affected product: Open-xchange Open-xchange Appsuite Backend
Published: 2023-08-02
Last modified: 2026-06-17

Description

Attackers with access to user accounts can inject arbitrary control characters to SIEVE mail-filter rules. This could be abused to access SIEVE extension that are not allowed by App Suite or to inject rules which would break per-user filter processing, requiring manual cleanup of such rules. We have added sanitization to all mail-filter APIs to avoid forwardning control characters to subsystems. No publicly available exploits are known.

Frequently asked questions

What is CVE-2023-26430?: Attackers with access to user accounts can inject arbitrary control characters to SIEVE mail-filter rules. This could be abused to access SIEVE extension that are not allowed by App Suite or to inject rules which would break per-user filter processing, requiring manual cleanup of such rules. We have added sanitization to all mail-filter APIs to avoid forwardning control characters to subsystems. No publicly available exploits are known.
How severe is CVE-2023-26430?: CVE-2023-26430 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2023-26430 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-26430?: CVE-2023-26430 primarily affects Open-xchange Open-xchange Appsuite Backend. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-26430?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-26430 published?: CVE-2023-26430 was published on 2023-08-02 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:open-xchange:open-xchange_appsuite_backend:7.10.6:*:*:*:*:*:*:*
cpe:2.3:a:open-xchange:open-xchange_appsuite_backend:8.10.0:*:*:*:*:*:*:*

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