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CVE-2026-62365

Wazuh: Heap Buffer Overflow in DecodeWinevt() join_data Accumulation via Crafted EventChannel XML

5.3 Medium

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. DecodeWinevt in src/analysisd/decoders/winevtchannel.c accumulates unnamed Windows EventChannel Data element contents into the fixed 65,535-byte join_data heap buffer but passes the growing content length, rather than the OS_MAXSTR buffer capacity, as the snprintf size. An enrolled agent can submit an EventChannel message containing four maximum-sized unnamed Data elements, causing the fourth accumulation to write beyond join_data and corrupt adjacent heap metadata. The subsequent free of join_data2 causes the wazuh-analysisd process to terminate, stopping log ingestion for all agents handled by that manager. This vulnerability is fixed in 4.14.7.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.28%Unchanged since Nov 5, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Wazuh: Heap Buffer Overflow in DecodeWinevt() join_data Accumulation via Crafted EventChannel XML

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. DecodeWinevt in src/analysisd/decoders/winevtchannel.c accumulates unnamed Windows EventChannel Data element contents into the fixed 65,535-byte join_data heap buffer but passes the growing content length, rather than the OS_MAXSTR buffer capacity, as the snprintf size. An enrolled agent can submit an EventChannel message containing four maximum-sized unnamed Data elements, causing the fourth accumulation to write beyond join_data and corrupt adjacent heap metadata. The subsequent free of join_data2 causes the wazuh-analysisd process to terminate, stopping log ingestion for all agents handled by that manager. This vulnerability is fixed in 4.14.7.

Record
CVE-2026-62365
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-122
Updated
2026-11-04
EUVDEUVD-2026-117190 5.3

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. DecodeWinevt in src/analysisd/decoders/winevtchannel.c accumulates unnamed Windows EventChannel Data element contents into the fixed 65,535-byte join_data heap buffer but passes the growing content length, rather than the OS_MAXSTR buffer capacity, as the snprintf size. An enrolled agent can submit an EventChannel message containing four maximum-sized unnamed Data elements, causing the fourth accumulation to write beyond join_data and corrupt adjacent heap metadata. The subsequent free of join_data2 causes the wazuh-analysisd process to terminate, stopping log ingestion for all agents handled by that manager. This vulnerability is fixed in 4.14.7.

Record
EUVD-2026-117190
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-05
NVD 5.3

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. DecodeWinevt in src/analysisd/decoders/winevtchannel.c accumulates unnamed Windows EventChannel Data element contents into the fixed 65,535-byte join_data heap buffer but passes the growing content length, rather than the OS_MAXSTR buffer capacity, as the snprintf size. An enrolled agent can submit an EventChannel message containing four maximum-sized unnamed Data elements, causing the fourth accumulation to write beyond join_data and corrupt adjacent heap metadata. The subsequent free of join_data2 causes the wazuh-analysisd process to terminate, stopping log ingestion for all agents handled by that manager. This vulnerability is fixed in 4.14.7.

Record
CVE-2026-62365
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-122
Updated
2026-11-07
OSV 5.3

Wazuh: Heap Buffer Overflow in DecodeWinevt() join_data Accumulation via Crafted EventChannel XML

Wazuh is an open-source security platform providing unified XDR and SIEM protection for endpoints and cloud workloads. DecodeWinevt in src/analysisd/decoders/winevtchannel.c accumulates unnamed Windows EventChannel Data element contents into the fixed 65,535-byte join_data heap buffer but passes the growing content length, rather than the OS_MAXSTR buffer capacity, as the snprintf size. An enrolled agent can submit an EventChannel message containing four maximum-sized unnamed Data elements, causing the fourth accumulation to write beyond join_data and corrupt adjacent heap metadata. The subsequent free of join_data2 causes the wazuh-analysisd process to terminate, stopping log ingestion for all agents handled by that manager. This vulnerability is fixed in 4.14.7.

Record
CVE-2026-62365
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-122
Updated
2026-11-08

Affected products

History

History
RecordedChangedSources
aliases, referencesNVD, OSV
aliases, publishedEUVD
first indexedCVE List

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-62365 is a medium vulnerability (CVSS 5.3) in Wazuh, published November 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 21st percentile. No source names a fixed version.

References

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