CVE-2020-26281

MEDIUMNVD 6.86.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.8 under NVD CVSS v3. EPSS exploit probability: 1.0%, top 41% 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
6.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.8Exploit: None knownExposed: 0

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

async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). There is a request smuggling vulnerability in async-h1 before version 2.3.0. This vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications. If the server does not read the body of a request which is longer than some buffer length, async-h1 will attempt to read a subsequent request from the body content starting at that offset into the body. One way to exploit this vulnerability would be for an adversary to craft a request such that the body contains a request that would not be noticed by a reverse proxy, allowing it to forge forwarded/x-forwarded headers. If an application trusted the authenticity of these headers, it could be misled by the smuggled request. Another potential concern with this vulnerability is that if a reverse proxy is sending multiple http clients' requests along the same keep-alive connection, it would be possible for the smuggled request to specify a long content and capture another user's request in its body. This content could be captured in a post request to an endpoint that allows the content to be subsequently retrieved by the adversary. This has been addressed in async-h1 2.3.0 and previous versions have been yanked.

CVSS v3
6.8
EG Score
6.8(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: Track

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
Severity68% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
62%
KEV
Not listed

Published

December 21, 2020

Last Modified

November 21, 2024

References (4)

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFixed inDependents
async-h1—2.3.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 23× 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 136 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2020-26281?
CVE-2020-26281 is a medium vulnerability published on December 21, 2020. async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). There is a request smuggling vulnerability in async-h1 before version 2.3.0. This vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications. If the server does not read the…
When was CVE-2020-26281 disclosed?
CVE-2020-26281 was first published in the National Vulnerability Database on December 21, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-26281 actively exploited?
CVE-2020-26281 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 38.2% of all scored CVEs.
What is the CVSS score of CVE-2020-26281?
CVE-2020-26281 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2020-26281?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-26281, 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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