# CVE-2026-43897: OP-Engineering link-preview-js SSRF via IPv6 and DNS loopback bypass

Source: https://junglewise.ai/threats/cve-2026-43897-op-engineering-link-preview-js-ssrf-via-ipv6-and-dns-loopback  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-43897 · Severity: high · CVSS 4 · Published 2026-05-11

link-preview-js is a JavaScript library that extracts metadata (title, description, images) from web links. The library failed to properly validate IPv6 loopback addresses and could be tricked via DNS resolution to access internal or private IP addresses, potentially leaking sensitive internal data. Attackers could exploit this to probe internal networks or retrieve metadata from services not intended to be publicly accessible.

Technologies: [OP-Engineering Link-Preview-Js](https://junglewise.ai/threats/technologies/link-preview-js). Vendors: [OP-Engineering](https://junglewise.ai/threats/vendors/op-engineering).

## Quick answers

**Is CVE-2026-43897 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-43897 being exploited in the wild.

**How severe is CVE-2026-43897?** High severity, with a CVSS score of 4, published 11 May 2026.

**Which products and versions are affected?** OP-Engineering Link-Preview-Js <= 4.0.0.

**Is there a fix for CVE-2026-43897?** A patch was published on 2026-04-25: Version 4.0.1 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-43897 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-43897?** Check whether you run OP-Engineering Link-Preview-Js at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a Server-Side Request Forgery (SSRF) vulnerability (CWE-918) in link-preview-js that allows attackers to bypass network access controls. The root cause is insufficient validation of IPv6 loopback addresses in the URL validation regex, and improper handling of DNS resolution results. An attacker can supply a URL that resolves to an internal IP address (127.0.0.1, ::1, or private ranges) or craft IPv6 addresses designed to reach loopback interfaces. The attack requires no authentication and is network-reachable. A successful exploit allows an attacker to fetch content from internal services, potentially exposing sensitive data or metadata. The patch in version 4.0.1 tightens the IPv6 validation regex and blocks certain DNS suffixes (.internal, .local, .nip.io, .sslip.io), but the maintainers acknowledge this is incomplete protection. Users are strongly advised to use the resolveDNSHost option to perform DNS resolution validation before fetching content.

## Affected products

- OP-Engineering link-preview-js <= 4.0.0

## Identifiers

- CVE-2026-43897
- GHSA-4gp8-rjrq-ch6q

## Timeline

- 2026-04-25: disclosed
- 2026-04-25: patched: Version 4.0.1 released
- 2026-05-05: advisory: GHSA-4gp8-rjrq-ch6q published

## References

- [https://github.com/OP-Engineering/link-preview-js/security/advisories/GHSA-4gp8-rjrq-ch6q](https://github.com/OP-Engineering/link-preview-js/security/advisories/GHSA-4gp8-rjrq-ch6q)
- [https://github.com/OP-Engineering/link-preview-js/pull/179](https://github.com/OP-Engineering/link-preview-js/pull/179)
- [https://github.com/OP-Engineering/link-preview-js/commit/4396d48909fab37553c0e93e26447fe218363ede](https://github.com/OP-Engineering/link-preview-js/commit/4396d48909fab37553c0e93e26447fe218363ede)
- [https://github.com/OP-Engineering/link-preview-js](https://github.com/OP-Engineering/link-preview-js)
- [https://github.com/OP-Engineering/link-preview-js/releases/tag/4.0.1](https://github.com/OP-Engineering/link-preview-js/releases/tag/4.0.1)

## Related threats

- [link-preview-js DNS rebinding SSRF bypass](https://junglewise.ai/threats/cve-2026-61704-link-preview-js-dns-rebinding-ssrf-bypass)