CVE-2026-58058: CVE-2026-58058: Nmap through 7.99 does not keep the IPv6 extension-header walk within the captured packet …
nmap · nmap · NVD published 2026-06-28 · posted 2026-08-17 · last modified 2026-06-30
What it is
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.
| Weakness | CWE-191 |
|---|---|
| CVSS vector | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (source: [email protected]) |
| ATT&CK tactics | n/a |
Exploitation evidence
First exploit evidence seen: 2026-08-17 (earliest date across the sources below).
Exploited in the wild
No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).
Public exploit code
Exploit-DB
- EDB-52647: Nmap 7.99 - Extension Header Integer Underflow (2026-08-17)
Sources: Exploit-DB (OffSec).
No ATT&CK techniques could be mapped or inferred for this CVE yet.
How to fix it
Fixed versions
- nmap nmap: versions up to and including 7.99 are affected; check the vendor advisory for the fixed release.
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://github.com/nmap/nmap/commit/bb6754e76bb1686315008e1aa1c40202a513fb83 (Patch)
- https://nmap.org/changelog.html (Patch, Release Notes)
- https://www.vulncheck.com/advisories/nmap-integer-underflow-in-ipv6-extension-header-parsing (Patch, Third Party Advisory)
Detection Generic guidance
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.