How to fix or mitigate CVE-2026-34865?

Within 24 hours: Inventory all HarmonyOS-based devices and systems in production; isolate or restrict network access to affected devices pending remediation. Within 7 days: Contact Huawei for security guidance and expected patch timeline; implement network segmentation to limit lateral movement if compromise occurs. Within 30 days: Apply vendor-released patch immediately upon availability; conduct forensic review of affected systems for indicators of compromise; validate remediation across the full device inventory.

CVE-2026-34865

Q: What is the CVSS score of CVE-2026-34865?

CVE-2026-34865 has a CVSS 4.0 base score of 10.0 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-21877 CRITICAL

Heap-based Buffer Overflow (CWE-122)

2026-04-13 huawei

GHSA-f3fr-gvgx-x9gh

Heap Overflow Buffer Overflow

10.0

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

10.0 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

Apr 17, 2026 - 19:37 vuln.today

cvss_changed

Analysis Generated

Apr 13, 2026 - 07:29 vuln.today

CVSS changed

Apr 13, 2026 - 07:22 NVD

10.0 (CRITICAL)

EUVD ID Assigned

Apr 13, 2026 - 07:15 euvd

EUVD-2026-21877

Analysis Generated

Apr 13, 2026 - 07:15 vuln.today

CVE Published

Apr 13, 2026 - 06:02 nvd

CRITICAL 10.0

DescriptionCVE.org

Out-of-bounds write vulnerability in the WEB module.Impact: Successful exploitation of this vulnerability will affect availability and confidentiality.

AnalysisAI

Out-of-bounds heap write in Huawei HarmonyOS WEB module allows unauthenticated remote attackers to execute arbitrary code and exfiltrate sensitive data with no user interaction required. CVSS v4.0 score of 10.0 (Critical) reflects network-based exploitation with low complexity requiring no privileges or user interaction. No public exploit identified at time of analysis. The vulnerability achieves complete compromise of confidentiality, integrity, and availability across both vulnerable and subsequent system scopes.

Technical ContextAI

This vulnerability is rooted in CWE-122 (heap-based buffer overflow) affecting the WEB module within Huawei's HarmonyOS platform (CPE: cpe:2.3:a:huawei:harmonyos). The WEB module likely handles browser rendering, WebView components, or web content processing. A heap-based buffer overflow occurs when the application writes data beyond allocated heap memory boundaries, typically due to insufficient bounds checking during memory operations. In modern web rendering engines, such flaws often arise in parsing HTML/CSS/JavaScript, processing media codecs, or handling network protocol data. The heap corruption can be leveraged to overwrite function pointers, vtables, or other control structures to redirect program execution. Given the cross-scope impact indicated in the CVSS vector (SC:H/SI:H/SA:H), successful exploitation allows the attacker to break out of the WEB module's sandbox and compromise other system components or data partitions.

RemediationAI

Apply security updates as detailed in Huawei's official security bulletin for wearables available at https://consumer.huawei.com/en/support/bulletinwearables/2026/4/. The vendor advisory should specify patched firmware versions for affected HarmonyOS devices. Users of HarmonyOS-based wearables and IoT devices should immediately check for available system updates through device settings or Huawei's support channels and apply patches as soon as released. Until patching is complete, consider restricting network exposure of affected devices, disabling unnecessary web-based features if possible, and monitoring for suspicious network activity. Organizations deploying HarmonyOS devices should prioritize patch deployment given the network-based attack vector and lack of authentication requirements.