CVE-2020-1045

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week

Also known asEUVD-2022-4249 (ENISA EUVD) · GHSA-hxrm-9w7p-39cc (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 5.9%CVSS: 7.5Exploit: None knownExposed services: Not assessed

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
7.5HIGHmedium confidence
EG Risk
51
EG Risk 51/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation5.9% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
5.9%
EPSS %ILE
93rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
5.9% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 11, 2020

Last Modified

February 23, 2026

Advisory Details (6)

Auto-updated Oct 29, 2026
Patch available. Sources: microsoft, redhat.
Web page

[SECURITY] Fedora 33 Update: dotnet3.1-3.1.108-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ASICXQXS4M7MTAF6SGQMCLCA63DLCUT3/
Web page

[SECURITY] Fedora 32 Update: dotnet3.1-3.1.108-1.fc32 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LN2FUVBSVPGK7AU3NMLO3YR6CGONQPB/
Web page

core/release-notes/3.1/3.1.8/3.1.8.md at main · dotnet/core · GitHub

https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2020:3699
Web page

Reliance on Untrusted Inputs in a Security Decision in dotnet | CVE-2020-1045 | Snyk

https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600
Microsoft

Security Update Guide - Microsoft Security Response Center

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045

Vendor Advisories for CVE-2020-1045(1)

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

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrh-dotnet31-dotnet-0:3.1.108-1.el72020-09-08redhat
redhatdotnet3.1-0:3.1.108-2.el8_22020-09-08redhat
nugetMicrosoft.AspNetCore.App @ 2.1.22 (fixes <= 2.1.21)—ghsa
nugetMicrosoft.AspNetCore.App.Runtime.linux-arm @ 3.1.8 (fixes >= 3.1.0, < 3.1.8)—ghsa
nugetMicrosoft.Owin @ 4.1.1 (fixes < 4.1.1)—ghsa

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 rangeFix by version rangeDependents
Microsoft.AspNetCore.App2.1.0 ... 2.1.9 (25 versions)
  • every version up to 2.1.22: fixed in 2.1.22
—
Microsoft.AspNetCore.App.Runtime.linux-arm3.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.linux-arm643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.linux-musl-arm643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.linux-musl-x643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.linux-x643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.osx-x643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.win-arm3.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.win-arm643.1.5, 3.1.6, 3.1.7
  • 3.1.5 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.win-x643.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.App.Runtime.win-x863.1.0 ... 3.1.7 (8 versions)
  • 3.1.0 up to 3.1.8: fixed in 3.1.8
—
Microsoft.AspNetCore.Http0.0.1-alpha ... 2.1.1 (22 versions)
  • every version up to 2.1.22: fixed in 2.1.22
—
Microsoft.Owin1.1.0-beta1 ... 4.1.0 (21 versions)
  • every version up to 4.1.1: fixed in 4.1.1
—

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 11× in last 7d / 40× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 190 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 93 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:29 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  2. 2026-11-01 08:39 UTCGHSA enrichmentGHSA-hxrm-9w7p-39cc · GitHub severity HIGH · GitHub CVSS 7.5
  3. 2026-11-01 08:39 UTCEG score recompute
  4. 2026-10-31 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  5. 2026-10-30 16:29 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  6. 2026-10-29 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  7. 2026-10-29 09:43 UTCEG score recompute
  8. 2026-10-29 09:43 UTCVendor advisory
  9. 2026-10-28 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  10. 2026-10-27 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  11. 2026-10-26 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  12. 2026-10-25 18:53 UTCEG score recompute
  13. 2026-10-25 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  14. 2026-10-24 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  15. 2026-10-23 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  16. 2026-10-22 16:29 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  17. 2026-10-21 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  18. 2026-10-21 16:04 UTCEG score recompute
  19. 2026-10-21 16:04 UTCVendor advisory
  20. 2026-10-20 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  21. 2026-10-19 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  22. 2026-10-19 08:25 UTCOSV refresh
  23. 2026-10-18 09:38 UTCEG score recompute
  24. 2026-10-17 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  25. 2026-10-16 16:33 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
Show 72 more
  1. 2026-10-15 16:27 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  2. 2026-10-14 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  3. 2026-10-13 16:28 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  4. 2026-10-12 19:49 UTCEG score recompute
  5. 2026-10-12 16:29 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  6. 2026-10-12 00:12 UTCEG score recompute
  7. 2026-10-11 13:43 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  8. 2026-10-10 19:56 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  9. 2026-10-09 20:04 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  10. 2026-10-08 16:38 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  11. 2026-10-07 23:44 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  12. 2026-10-06 15:13 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  13. 2026-10-05 17:39 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  14. 2026-10-04 23:18 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  15. 2026-10-03 14:22 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  16. 2026-10-02 16:22 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  17. 2026-09-30 14:59 UTCEPSS rescoreEPSS 5.9% · 93rd percentile
  18. 2026-09-30 10:31 UTCEG score recompute
  19. 2026-09-27 13:40 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  20. 2026-09-26 16:50 UTCOSV refresh
  21. 2026-09-26 15:54 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  22. 2026-09-26 00:20 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  23. 2026-09-24 14:00 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  24. 2026-09-22 14:43 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  25. 2026-09-21 20:28 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  26. 2026-09-20 20:11 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  27. 2026-09-18 19:23 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  28. 2026-09-17 19:22 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  29. 2026-09-16 14:04 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  30. 2026-09-15 03:06 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  31. 2026-09-13 16:42 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  32. 2026-09-12 14:56 UTCEPSS rescoreEPSS 5.9% · 92nd percentile
  33. 2026-09-11 14:48 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  34. 2026-09-11 09:32 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  35. 2026-09-10 09:29 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  36. 2026-09-08 21:56 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  37. 2026-09-07 02:18 UTCOSV refresh
  38. 2026-09-06 13:44 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  39. 2026-09-05 15:24 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  40. 2026-09-04 13:57 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  41. 2026-09-04 05:03 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  42. 2026-09-02 14:08 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  43. 2026-09-01 03:32 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  44. 2026-08-30 19:14 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  45. 2026-08-30 01:18 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  46. 2026-08-27 14:21 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  47. 2026-08-26 14:42 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  48. 2026-08-25 13:45 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  49. 2026-08-21 23:45 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  50. 2026-08-20 22:52 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  51. 2026-08-20 12:01 UTCOSV refresh
  52. 2026-08-19 17:00 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  53. 2026-08-18 13:44 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  54. 2026-08-16 14:52 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  55. 2026-08-16 02:11 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  56. 2026-08-15 01:26 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  57. 2026-08-13 21:57 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  58. 2026-08-12 13:47 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  59. 2026-08-08 16:33 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  60. 2026-08-07 16:23 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  61. 2026-08-06 13:43 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  62. 2026-08-05 19:14 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  63. 2026-08-05 07:40 UTCOSV refresh
  64. 2026-08-04 15:06 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  65. 2026-08-04 10:34 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  66. 2026-08-03 10:32 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  67. 2026-08-02 02:23 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  68. 2026-08-01 04:12 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  69. 2026-07-30 16:25 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  70. 2026-07-30 01:27 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  71. 2026-07-28 15:32 UTCEPSS rescoreEPSS 6.0% · 92nd percentile
  72. 2026-07-25 14:15 UTCEPSS rescoreEPSS 6.0% · 92nd percentile

Frequently asked(5)

What is CVE-2020-1045?
CVE-2020-1045 is a high-severity vulnerability; its CVE record was 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 made public?
CVE-2020-1045 was made public on September 8, 2020: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on September 11, 2020. EchelonGraph's copy of the record carries a last-modified date of February 23, 2026; the record at its source may have been updated since.
Is CVE-2020-1045 actively exploited?
CVE-2020-1045 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.9% probability of exploitation in the next 30 days (93rd percentile of EPSS-scored CVEs).
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?
A fix for CVE-2020-1045 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2020-1045 are linked in the Vendor Advisories panel on this page.

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