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Fencer Vulns
medium 6.5

CVE-2026-41499 json

Wazuh: Multiple Heap-based NULL WRITE Buffer Underflows in parse_uname_string()

published 2026-04-29 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-26272

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

Wazuh is a free and open source platform used for threat prevention, detection, and response. From version 4.0.0 to before version 4.14.4, multiple heap-based out-of-bounds WRITE vulnerabilities exist in parse_uname_string() (remoted_op.c). This function processes OS identification data from agents and contains a dangerous code pattern that appears in 4 locations within the same function: writing to strlen(ptr) - 1 without checking for empty strings. When the string is empty, strlen() returns 0, and 0 - 1 wraps to SIZE_MAX due to unsigned integer underflow. Due to pointer arithmetic wrapping, SIZE_MAX effectively becomes -1, causing a write exactly 1 byte before the allocated buffer. This corrupts heap metadata (e.g., the chunk size field in glibc malloc), leading to heap corruption. This issue has been patched in version 4.14.4.

Patch / fix

  • wazuh wazuh 4.14.4

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/wazuh/wazuh/security/advisories/GHSA-qvqj-p8mm-r7h3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • wazuh wazuh

Classification

Weakness
  • CWE-124 Buffer Underwrite
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.