CVE-2026-18738 json
Shlink CSV Formula Injection via Visit Export CLI
published 3mo ago modified 17d ago also EUVD-2026-52439
- cvss
- 4.7
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
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.
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3mo ago
Exploit prediction
0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 4.7 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N |
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/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 |
Affected products
- shlinkio Shlink
Classification
- Weakness
-
- CWE-1236 Improper Neutralization of Formula Elements in a CSV File
References
-
github.com
/theopaid/CSV-formula-injection-in-visit-exports-shlink-
vendor-advisory
-
github.com
/shlinkio/shlink
product
-
vulncheck.com
/advisories/shlink-csv-formula-injection-via-visit-export-cli
third-party-advisory
Sources
- CVE List CVE-2026-18738
- NVD CVE-2026-18738
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