CVE-2026-58058

Nmap - Integer Underflow in IPv6 Extension Header Parsing

CVSS 6.9 MEDIUMEPSS 0.3%CWE-191

Vexday Risk Score

33Attention

SSVC decision (CISA)

Attend

PoC available → attend closely

CVSS 6.9EPSS 0.3%KEV nãoPoC públicaNuclei —Metasploit —Patch referenciado

Lifecycle

28 Jun 2026Published on NVD

Recommendation: Plan a near-term fix — a public PoC already exists.

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

Affected products

Nmap · Nmap

public PoCs found — 1

cve_referencegithub.com/bikini/exploitarium/tree/main/nmap-ipv6-extlen-wrap-pocunverified

⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.

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References

https://github.com/bikini/exploitarium/tree/main/nmap-ipv6-extlen-wrap-poc https://github.com/nmap/nmap/commit/bb6754e76bb1686315008e1aa1c40202a513fb83 https://nmap.org/changelog.html https://www.vulncheck.com/advisories/nmap-integer-underflow-in-ipv6-extension-header-parsing