CVE-2026-58058

Nmap - Integer Underflow in IPv6 Extension Header Parsing

MEDIUM
6.5
CVSS Score
Published: June 28, 2026 at 01:32 AM UTC
Updated: October 25, 2026 at 05:10 PM UTC
1 product affected across 1 vendorNmap

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Severity
MEDIUM6.5
Exploit prediction
EPSS 1%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 7.99

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-191

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