CVE-2026-58058
Nmap - Integer Underflow in IPv6 Extension Header Parsing
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-191 |
| Vendor | nmap |
| Product | nmap |
| Published | Jun 28, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low
Affected Versions
Nmap / Nmap
0 ≤ 7.99
References
github.com: https://github.com/bikini/exploitarium/tree/main/nmap-ipv6-extlen-wrap-poc github.com: https://github.com/nmap/nmap/commit/bb6754e76bb1686315008e1aa1c40202a513fb83 nmap.org: https://nmap.org/changelog.html vulncheck.com: https://www.vulncheck.com/advisories/nmap-integer-underflow-in-ipv6-extension-header-parsing
Credits
Himanshu Anand