CVE-2020-1045

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 20.4%, top 4% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 7%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names. The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded. The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
93.1%
KEV
Not listed

Published

September 11, 2020

Last Modified

February 23, 2026

References (12)

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrh-dotnet31-dotnet-0:3.1.108-1.el72020-09-08redhat
redhatdotnet3.1-0:3.1.108-2.el8_22020-09-08redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(13 across 1 ecosystem)
NuGet(13)
PackageVulnerable rangeFixed inDependents
Microsoft.AspNetCore.App2.1.0 ... 2.1.9 (25 versions)2.1.22—
Microsoft.AspNetCore.App.Runtime.linux-arm3.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.linux-arm643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.linux-musl-arm643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.linux-musl-x643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.linux-x643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.osx-x643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.win-arm3.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.win-arm643.1.5, 3.1.6, 3.1.73.1.8—
Microsoft.AspNetCore.App.Runtime.win-x643.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.App.Runtime.win-x863.1.0 ... 3.1.7 (8 versions)3.1.8—
Microsoft.AspNetCore.Http0.0.1-alpha ... 2.1.1 (22 versions)2.1.22—
Microsoft.Owin1.1.0-beta1 ... 4.1.0 (21 versions)4.1.1—

All Vendor Advisories

(3)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 10× in last 7d / 41× 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.

  1. 2026-07-11 08:25 UTCEPSS rescore
  2. 2026-07-11 08:25 UTCEPSS rescore
  3. 2026-07-09 19:07 UTCEPSS rescore
  4. 2026-07-08 15:12 UTCEPSS rescore
  5. 2026-07-07 13:43 UTCEPSS rescore
  6. 2026-07-07 13:43 UTCEPSS rescore
  7. 2026-07-06 16:25 UTCEPSS rescore
  8. 2026-07-06 16:25 UTCEPSS rescore
  9. 2026-07-06 02:21 UTCEPSS rescore
  10. 2026-07-06 02:21 UTCEPSS rescore
  11. 2026-07-05 02:27 UTCEPSS rescore
  12. 2026-07-04 06:29 UTCEPSS rescore
  13. 2026-07-04 06:28 UTCEPSS rescore
  14. 2026-07-01 15:03 UTCEPSS rescore
  15. 2026-07-01 12:16 UTCOSV refresh
  16. 2026-06-30 23:20 UTCEPSS rescore
  17. 2026-06-30 23:20 UTCEPSS rescore
  18. 2026-06-28 14:05 UTCEPSS rescore
  19. 2026-06-28 04:54 UTCEPSS rescore
  20. 2026-06-28 04:54 UTCEPSS rescore
  21. 2026-06-27 03:06 UTCEPSS rescore
  22. 2026-06-25 13:47 UTCEPSS rescore
  23. 2026-06-24 14:03 UTCEPSS rescore
  24. 2026-06-24 14:03 UTCEPSS rescore
  25. 2026-06-23 21:31 UTCEPSS rescore
Show 45 more
  1. 2026-06-23 21:31 UTCEPSS rescore
  2. 2026-06-22 14:23 UTCEPSS rescore
  3. 2026-06-22 14:23 UTCEPSS rescore
  4. 2026-06-21 01:57 UTCEPSS rescore
  5. 2026-06-21 01:57 UTCEPSS rescore
  6. 2026-06-19 19:23 UTCEPSS rescore
  7. 2026-06-18 17:50 UTCEPSS rescore
  8. 2026-06-17 17:50 UTCEPSS rescore
  9. 2026-06-16 17:50 UTCEPSS rescore
  10. 2026-06-16 17:50 UTCEPSS rescore
  11. 2026-06-15 17:46 UTCEPSS rescore
  12. 2026-06-14 23:15 UTCEPSS rescore
  13. 2026-06-13 22:58 UTCEPSS rescore
  14. 2026-06-13 22:58 UTCEPSS rescore
  15. 2026-06-13 19:13 UTCOSV refresh
  16. 2026-06-12 23:10 UTCEPSS rescore
  17. 2026-06-11 13:58 UTCEPSS rescore
  18. 2026-06-10 22:16 UTCEPSS rescore
  19. 2026-06-10 22:16 UTCEPSS rescore
  20. 2026-06-10 13:20 UTCEPSS rescore
  21. 2026-06-08 14:15 UTCEPSS rescore
  22. 2026-06-08 14:15 UTCEPSS rescore
  23. 2026-06-07 15:23 UTCEPSS rescore
  24. 2026-06-07 15:23 UTCEPSS rescore
  25. 2026-06-06 13:45 UTCEPSS rescore
  26. 2026-06-06 13:45 UTCEPSS rescore
  27. 2026-06-05 22:45 UTCEPSS rescore
  28. 2026-06-05 22:45 UTCEPSS rescore
  29. 2026-06-04 13:10 UTCEPSS rescore
  30. 2026-06-04 13:10 UTCEPSS rescore
  31. 2026-06-02 20:11 UTCEPSS rescore
  32. 2026-06-02 20:11 UTCEPSS rescore
  33. 2026-05-31 22:29 UTCEPSS rescore
  34. 2026-05-31 22:29 UTCEPSS rescore
  35. 2026-05-31 00:15 UTCEPSS rescore
  36. 2026-05-31 00:15 UTCEPSS rescore
  37. 2026-05-29 13:42 UTCEPSS rescore
  38. 2026-05-28 13:43 UTCEPSS rescore
  39. 2026-05-28 13:43 UTCEPSS rescore
  40. 2026-05-27 13:39 UTCEPSS rescore
  41. 2026-05-26 23:14 UTCEG score recompute
  42. 2026-05-26 23:14 UTCVendor advisory
  43. 2026-05-26 07:17 UTCEPSS rescore
  44. 2026-05-26 07:17 UTCEPSS rescore
  45. 2026-05-24 16:48 UTCEPSS rescore

Frequently asked(5)

What is CVE-2020-1045?
CVE-2020-1045 is a high vulnerability published on September 11, 2020. <p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p> <p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p> <p>The security…
When was CVE-2020-1045 disclosed?
CVE-2020-1045 was first published in the National Vulnerability Database on September 11, 2020, with the most recent update on February 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-1045 actively exploited?
CVE-2020-1045 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 93.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-1045?
CVE-2020-1045 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2020-1045?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-1045, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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