CVE intelligence

CVE-2026-58058

Vulnerability intelligence

Published Jun 28, 2026Sources checked Nov 12, 2026

6.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-58058 and is rated Medium severity with a CVSS score of 6.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

Public exploit: Cataloged public exploit.

Exploit-DB: Nmap 7.99 - Extension Header Integer Underflow (2026-09-23 21:40:27.335989+00)
Exploit-DB lists a public exploit or proof of concept for this CVE. SecurityAlert has not executed it; this is not evidence of attacks against your systems.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 22, 2026

CBL-Mariner Releases Release Notes

Vendor-listed releases

7.95-4
4:4:7.92-12.azl4

CISA KEVNot listedBased on the latest collected catalog

EPSS1.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-58058?

Nmap through 7.99 does not keep the IPv6 extension-header walk within the captured packet in ipv6_get_data_primitive (libnetutil/netutil.cc), so the pointer advances past the buffer and the remaining-length computation underflows to a large value. A scanned target or on-path attacker returning a crafted IPv6 response with a truncated extension header can trigger out-of-bounds reads and a crash during raw IPv6 scans.

Source: NVD