Cyber Resilience

CVE-2026-34824

Memory Safety in Mesop-Dev Mesop 1.2.3 – 1.2.5

Published
03 April 2026
Modified
24 July 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0072 51th percentile
Risk Priority 59 floored blend · peak EPSS

Summary

CVE-2026-34824 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Mesop-Dev Mesop. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked in the top 49% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-10 (Concurrent Session Control) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-34824 is an uncontrolled resource consumption vulnerability in the WebSocket implementation of the Mesop framework, a Python-based tool for building web applications. It affects Mesop versions from 1.2.3 up to but not including 1.2.5. The flaw allows an unauthenticated attacker to send a rapid succession of WebSocket messages, causing the server to spawn an unbounded number of operating system threads. This results in thread exhaustion and Out of Memory (OOM) errors, leading to a complete Denial of Service (DoS) condition for any application built on the framework. The vulnerability is rated with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and is associated with CWEs-125 and CWE-770.

An unauthenticated remote attacker can exploit this vulnerability over the network with low complexity and no privileges required. By flooding the WebSocket endpoint with messages, the attacker forces excessive thread creation, quickly depleting server resources and rendering the application unresponsive. The impact is strictly on availability, with no confidentiality or integrity effects, but it can fully disrupt services hosted on affected Mesop instances.

The issue has been addressed in Mesop version 1.2.5, as detailed in the project's GitHub security advisory (GHSA-3jr7-6hqp-x679), release notes, and the patching commit (760a2079b5c609038c826d24dfbcf9b0be98d987). Security practitioners should upgrade to version 1.2.5 or later and review WebSocket handling in custom applications for similar resource exhaustion risks.

EU & UK References

Vulnerability Data

Mesop is a Python-based UI framework that allows users to build web applications. From version 1.2.3 to before version 1.2.5, an uncontrolled resource consumption vulnerability exists in the WebSocket implementation of the Mesop framework. An unauthenticated attacker can send a…

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rapid succession of WebSocket messages, forcing the server to spawn an unbounded number of operating system threads. This leads to thread exhaustion and Out of Memory (OOM) errors, causing a complete Denial of Service (DoS) for any application built on the framework. This issue has been patched in version 1.2.5.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
T1498.001 Direct Network Flood Impact
Adversaries may attempt to cause a denial of service (DoS) by directly sending a high-volume of network traffic to a target.
T1498.002 Reflection Amplification Impact
Adversaries may attempt to cause a denial of service (DoS) by reflecting a high-volume of network traffic to a target.
T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-1544Shared CWE-125, CWE-770
CVE-2026-27880Shared CWE-125, CWE-770
CVE-2023-0568Shared CWE-770
CVE-2023-26285Shared CWE-770
CVE-2023-39180Shared CWE-125
CVE-2023-24862Shared CWE-125
CVE-2023-26157Shared CWE-125
CVE-2026-65819Shared CWE-125
CVE-2024-46891Shared CWE-125
CVE-2023-47746Shared CWE-770

Affected Assets

mesop-dev
mesop
1.2.3 — 1.2.5

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V15.4.4

Mitigating Controls (NIST 800-53 r5) AI

Directly enforces a hard limit on concurrent sessions, structurally preventing unbounded resource allocation.

Developer testing and evaluation directly finds out-of-bounds read flaws through static analysis, fuzzing, and dynamic bounds checks.

Requires explicit allocation of resources by priority or quota, directly stopping unlimited allocation.

Imposes a limit on consecutive invalid attempts, preventing one specific class of unbounded resource consumption.

Secure engineering principles require bounds checking and memory-safe constructs that stop out-of-bounds reads from being introduced.

Process isolation confines the effects of an out-of-bounds read to the compromised process.

Mitigating Controls (NIST CSF 2.0) AI

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

PR.IR-04 mostly match
degrades

Monitoring capacity and taking action to maintain availability directly reduces unchecked resource allocation.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

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

Baseline comparison of CPU, memory and bandwidth usage helps surface uncontrolled resource allocations before they cause service degradation.

finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

prevents

Capacity projections and elasticity measures ensure that allocation requests are bounded and can be throttled, reducing the window in which an attacker can force unbounded resource reservations.

mitigates

Defining retention periods and deletion schedules for backup copies prevents indefinite accumulation of data on storage media without corresponding resource-management controls.

mitigates

Architectural redundancy and automatic failover limit the impact of an attacker who forces excessive allocations, because spare capacity can absorb the load until the primary instance recovers.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
  • V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
Oracle Linux 9 (2 rules)
  • V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
  • V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
RHEL 8 (1 rule)
  • V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770

References