Lancet through 2.3.9 SSRF Protection Bypass via netutil.IsInternalIP

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-110240
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-13 19:18:49 UTC
Updated2026-10-13 20:17:28 UTC
DescriptionLancet through 2.3.9 contains an SSRF protection bypass vulnerability in netutil.IsInternalIP that misclassifies IPv6 private, link-local, CGNAT and transition addresses as external. Attackers can supply hostnames resolving to these address forms, including NAT64, 6to4 or Teredo embedding internal IPv4, to reach internal services or cloud metadata endpoints.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from [email protected]

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

Problem Types: CWE-918 | CWE-918 Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
3.1[email protected]Secondary4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1CNACVSS4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
None

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

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Duke-git Lancet affected 2.1.2 2.3.9 semver Not specified
CNA Duke-git Lancet affected 1.3.1 1.4.6 semver Not specified

References

ReferenceSourceLinkTags
github.com/duke-git/lancet/commit/835111c832939a85416d686a1e99d5fe7060c9b4 [email protected] github.com
github.com/duke-git/lancet/blob/v1.4.6/netutil/net.go [email protected] github.com
www.vulncheck.com/advisories/lancet-through-2.3.9-ssrf-protection-bypass-via-ne... [email protected] www.vulncheck.com
github.com/duke-git/lancet [email protected] github.com
github.com/duke-git/lancet/blob/v2.3.9/netutil/net.go [email protected] github.com
github.com/duke-git/lancet/issues/356 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/duke-git/lancet/pull/357 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: George Chen (en)

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