Security Resilience

CVE-2023-26432

DoS in Open-Xchange Appsuite Backend ≤ 7.10.6

Public PoCDoS
Published
20 June 2023
Modified
21 November 2024
CVSS Score v3.1 4.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.011 66th percentile
Risk Priority 39 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-26432 is a medium-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Open-Xchange Open-Xchange Appsuite Backend. Its CVSS base score is 4.3 (Medium).

Operationally, ranked in the top 34% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability Data

When adding an external mail account, processing of SMTP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue SMTP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now…

more

limit accepted SMTP server response to reasonable length/size. No publicly available exploits are known.

CWE(s)

Related Threats

CVEs Like This One

CVE-2023-26434Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26433Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26431Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26435Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26438Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26443Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26430Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26451Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26429Same product: Open-Xchange Open-Xchange Appsuite Backend
CVE-2023-26427Same product: Open-Xchange Open-Xchange Appsuite Backend

Affected Assets

open-xchange
open-xchange appsuite backend
7.10.6 · ≤ 7.10.6 · 8.0.0 — 8.11.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-400

Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.

addresses: CWE-400

Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.

addresses: CWE-400

Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.

addresses: CWE-400

Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.

addresses: CWE-400

Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.

addresses: CWE-400

Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.

addresses: CWE-400

The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.

addresses: CWE-400

Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.

finds

Early notification of anomalous resource consumption or system malfunctions enables throttling or isolation before availability is lost.

A.8.15 Logging partial match
finds

Specifying log storage limits and rotation procedures reduces the risk that unbounded log growth will exhaust disk or memory resources and cause denial of service.

finds

Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.

blocks

A.8.20 implements network-level protections (firewalls, segmentation, protocol hardening, monitoring, authentication of systems/devices) that can limit abuse of a resource-consuming weakness but do not stop the weakness from being exploitable; the flaw remains present in the product and can still be triggered from an authorized or internal context.

blocks

Monitoring network service usage and applying controls to restrict access when necessary limits an attacker’s ability to consume excessive resources through unrestricted or unauthenticated service calls.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-400, a class-level weakness. Rules are authored against its narrower children: CWE-770.

References