CVE-2026-18738

MEDIUMPre-NVD 4.74.7—
EchelonGraph scoreMEDIUM confidence

Score 4.7 from GitHub Security Advisory published 2026-08-03. A secondary CVSS source baseline 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
4.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 4.7Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

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.

CVSS v3
4.7
EG Score
4.7MEDIUMmedium confidence
EG Risk
36
EG Risk 36/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity47% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.5%
EPSS %ILE
40th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 3, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Aug 3, 2026
🔬 Proof of concept available. No fix on record yet.
generic

Shlink CSV Formula Injection via Visit Export CLI | Advisories | VulnCheck

https://www.vulncheck.com/advisories/shlink-csv-formula-injection-via-visit-export-cli
generic🟡 PoC Available

GitHub - theopaid/CSV-formula-injection-in-visit-exports-shlink-: Security Advisory: CSV formula injection in visit exports (shlink) · GitHub

https://github.com/theopaid/CSV-formula-injection-in-visit-exports-shlink-
generic

GitHub - shlinkio/shlink: The definitive self-hosted URL shortener · GitHub

https://github.com/shlinkio/shlink

Vendor Advisories for CVE-2026-18738(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 58× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 154 total refreshes for this CVE.

  1. 2026-10-09 20:06 UTCEPSS rescore
  2. 2026-10-08 17:11 UTCEPSS rescore
  3. 2026-10-07 23:47 UTCEPSS rescore
  4. 2026-10-06 23:45 UTCEG score recompute
  5. 2026-10-06 23:45 UTCGHSA enrichment
  6. 2026-10-06 15:17 UTCEPSS rescore
  7. 2026-10-05 19:46 UTCEG score recompute
  8. 2026-10-05 19:46 UTCGHSA enrichment
  9. 2026-10-05 17:42 UTCEPSS rescore
  10. 2026-10-04 23:21 UTCEPSS rescore
  11. 2026-10-04 06:17 UTCEG score recompute
  12. 2026-10-04 06:17 UTCGHSA enrichment
  13. 2026-10-02 10:17 UTCEG score recompute
  14. 2026-10-02 10:17 UTCGHSA enrichment
  15. 2026-10-01 19:49 UTCEPSS rescore
  16. 2026-10-01 02:31 UTCEG score recompute
  17. 2026-10-01 02:31 UTCGHSA enrichment
  18. 2026-09-30 15:02 UTCEPSS rescore
  19. 2026-09-29 15:20 UTCEPSS rescore
  20. 2026-09-29 06:32 UTCEG score recompute
  21. 2026-09-29 06:32 UTCGHSA enrichment
  22. 2026-09-28 13:51 UTCEPSS rescore
  23. 2026-09-27 18:14 UTCEG score recompute
  24. 2026-09-27 18:14 UTCGHSA enrichment
  25. 2026-09-27 13:47 UTCEPSS rescore
Show 75 more
  1. 2026-09-26 15:58 UTCEPSS rescore
  2. 2026-09-24 08:20 UTCEG score recompute
  3. 2026-09-24 08:20 UTCGHSA enrichment
  4. 2026-09-23 06:06 UTCEG score recompute
  5. 2026-09-23 06:06 UTCGHSA enrichment
  6. 2026-09-22 03:52 UTCEG score recompute
  7. 2026-09-22 03:52 UTCGHSA enrichment
  8. 2026-09-20 11:04 UTCEG score recompute
  9. 2026-09-20 11:04 UTCGHSA enrichment
  10. 2026-09-19 08:00 UTCEG score recompute
  11. 2026-09-19 08:00 UTCGHSA enrichment
  12. 2026-09-18 19:27 UTCEPSS rescore
  13. 2026-09-18 03:27 UTCEG score recompute
  14. 2026-09-18 03:27 UTCGHSA enrichment
  15. 2026-09-17 01:13 UTCEG score recompute
  16. 2026-09-17 01:13 UTCGHSA enrichment
  17. 2026-09-16 14:07 UTCEPSS rescore
  18. 2026-09-16 05:14 UTCEPSS rescore
  19. 2026-09-15 16:54 UTCEG score recompute
  20. 2026-09-15 16:54 UTCGHSA enrichment
  21. 2026-09-14 07:55 UTCEG score recompute
  22. 2026-09-14 07:55 UTCGHSA enrichment
  23. 2026-09-13 16:46 UTCEPSS rescore
  24. 2026-09-13 05:41 UTCEG score recompute
  25. 2026-09-13 05:41 UTCGHSA enrichment
  26. 2026-09-12 15:00 UTCEPSS rescore
  27. 2026-09-12 03:27 UTCEG score recompute
  28. 2026-09-12 03:27 UTCGHSA enrichment
  29. 2026-09-11 14:52 UTCEPSS rescore
  30. 2026-09-11 09:36 UTCEPSS rescore
  31. 2026-09-11 01:12 UTCEG score recompute
  32. 2026-09-11 01:12 UTCGHSA enrichment
  33. 2026-09-10 09:34 UTCEPSS rescore
  34. 2026-09-09 21:04 UTCGHSA enrichment
  35. 2026-09-09 06:42 UTCEG score recompute
  36. 2026-09-09 06:42 UTCGHSA enrichment
  37. 2026-09-08 22:00 UTCEPSS rescore
  38. 2026-09-07 18:46 UTCEG score recompute
  39. 2026-09-07 18:46 UTCGHSA enrichment
  40. 2026-09-07 16:01 UTCEPSS rescore
  41. 2026-09-06 13:47 UTCEPSS rescore
  42. 2026-09-06 06:32 UTCEG score recompute
  43. 2026-09-06 06:32 UTCGHSA enrichment
  44. 2026-09-05 04:17 UTCEG score recompute
  45. 2026-09-05 04:17 UTCGHSA enrichment
  46. 2026-09-04 05:06 UTCEPSS rescore
  47. 2026-09-03 17:49 UTCEG score recompute
  48. 2026-09-03 17:49 UTCGHSA enrichment
  49. 2026-09-02 14:11 UTCEPSS rescore
  50. 2026-09-02 07:47 UTCEG score recompute
  51. 2026-09-02 07:47 UTCGHSA enrichment
  52. 2026-09-01 13:53 UTCEPSS rescore
  53. 2026-09-01 04:39 UTCEPSS rescore
  54. 2026-09-01 02:54 UTCGHSA enrichment
  55. 2026-08-31 00:10 UTCEG score recompute
  56. 2026-08-31 00:10 UTCGHSA enrichment
  57. 2026-08-30 19:17 UTCEPSS rescore
  58. 2026-08-30 01:22 UTCEPSS rescore
  59. 2026-08-29 21:56 UTCEG score recompute
  60. 2026-08-29 21:56 UTCGHSA enrichment
  61. 2026-08-28 21:41 UTCEPSS rescore
  62. 2026-08-27 20:02 UTCEG score recompute
  63. 2026-08-27 20:02 UTCGHSA enrichment
  64. 2026-08-27 14:25 UTCEPSS rescore
  65. 2026-08-26 14:46 UTCEPSS rescore
  66. 2026-08-26 13:39 UTCEG score recompute
  67. 2026-08-26 13:39 UTCGHSA enrichment
  68. 2026-08-25 13:48 UTCEPSS rescore
  69. 2026-08-25 11:25 UTCEG score recompute
  70. 2026-08-25 11:25 UTCGHSA enrichment
  71. 2026-08-24 09:04 UTCGHSA enrichment
  72. 2026-08-23 06:49 UTCEG score recompute
  73. 2026-08-23 06:49 UTCGHSA enrichment
  74. 2026-08-23 00:19 UTCEPSS rescore
  75. 2026-08-22 04:35 UTCEG score recompute

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Frequently asked(5)

What is CVE-2026-18738?
CVE-2026-18738 is a medium vulnerability published on August 3, 2026. 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…
When was CVE-2026-18738 disclosed?
CVE-2026-18738 was first published on August 3, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18738 actively exploited?
CVE-2026-18738 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18738?
CVE-2026-18738 has a CVSS base score of 4.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-18738?
No fix for CVE-2026-18738 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-18738 are linked in the Vendor Advisories panel on this page.

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