Vulnerability · Published Aug 3, 2026 · Assigned by VulnCheck

CVE-2026-18738Shlink CSV Formula Injection via Visit Export CLI

Medium 4.7

In plain English

A medium-severity security flaw in Shlink from shlinkio. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).

Severity (CVSS 3.1)4.7Medium

Exploit odds (30 days)0.5%top 57.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Shlink versions 5.0.0 through 5.1.5 contain a CSV formula injection vulnerability that allows unauthenticated remote attackers to plant spreadsheet formulas into exported visit data by supplying malicious values in User-Agent, Referer, or request path headers beginning with formula-triggering characters such as =, +, -, or @. Attackers can craft a single unauthenticated request against any short URL to embed DDE or WEBSERVICE formula payloads into CSV cells, which are then executed on an administrator's client machine when the exported CSV file is opened in a spreadsheet application that evaluates formulas.

Affected products (as reported)

Vendor	Product	Versions
shlinkio	Shlink	5.0.0 – through 5.1.5

Weakness: CWE-1236 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N

References

GitHub Security Advisory vendor-advisory
Product Repository product
https://www.vulncheck.com/advisories/shlink-csv-formula-injection-via-visit-export-cli third-party-advisory