CVE-2026-58058: Nmap - Integer Underflow in IPv6 Extension Header Parsing

mediumpublic exploitCVSS 6.5CVE-2026-58058

CSIRTS triage

product: NmapOther

What: There is an integer underflow in IPv6 extension header parsing.
Who is affected: Users of Nmap are affected.
Urgency: This vulnerability has a medium severity rating (CVSS 6.5), indicating a moderate urgency for remediation.
Action: Update to the latest version of Nmap to fix the integer underflow issue.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.5
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58058

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-580580.88% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 56% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-58058	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] nmap: Vulnerability allows denial of servicecert-bund
unknownMultiple vulnerabilities in Microsoft Azure Linux (July 7, 2026)cert-fr-avis
mediumCVE-2026-58058: Nmap through 7.99 does not keep the IPv6 extension-header walk within the captured packet in i…nvd

Recent advisories for Nmap - Integer

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-76372: In Nmap Scanner versions below 3.0.15, a user who holds a role that can edit, create, or run p…nvd · 2026-08-19
medium[UPDATE] [medium] nmap: Vulnerability allows denial of servicecert-bund · 2026-08-18
medium[NEW] [medium] nmap: Vulnerability enables Denial of Servicecert-bund · 2026-08-12
mediumCVE-2026-72712: Nmap versions up to and including 7.99 contains a denial of service vulnerability that allows …nvd · 2026-08-11
mediumCVE-2026-72712: Nmap 7.99 Denial of Service via Zero-Length TCP Option Packetmsrc · 2026-08-11
medium[NEW] [medium] nmap: Vulnerability allows denial of servicecert-bund · 2026-07-30