CVE-2026-54590

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
5.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.9Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
43
EG Risk 43/100

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 (value × EchelonGraph’s weight)
Severity59% × 45%
The EG Score, 5.9 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.4%
EPSS %ILE
31st
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (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

July 8, 2026

Last Modified

July 10, 2026

Advisory Details (2)

Auto-updated Jul 8, 2026
Patch available. Sources: github, github_commit.
GitHub commit

commit 3d515ba9ba0c (ronf/asyncssh)

Fix landed in ronf/asyncssh commit 3d515ba9ba0c — awaiting tagged release

https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88
GitHub advisoryMentions a patch (unverified)

Incomplete fix for CVE-2026-45309 — AuthorizedKeysFile %u still escapes the intended directory via a leading ~ (and weakly via ${ENV}) username substitution · Advisory · ronf/asyncssh · GitHub

Affected: v2.23.0, commit 2af2382) added a blocklist in

https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh

Vendor Advisories for CVE-2026-54590(1)

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

Affected Packages

(2 across 2 ecosystems)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-asyncssh2.20.0-1 ... 2.23.0-1 (6 versions)
  • every version up to 2.24.0-1: fixed in 2.24.0-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
asyncssh0.8.1 ... 2.9.0 (90 versions)
  • every version up to 2.23.1: fixed in 2.23.1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 34× 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 100 of 129 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. None are among the latest 100 rows. The 29 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 19:39 UTCEG score recompute
  2. 2026-10-11 16:54 UTCEG score recompute
  3. 2026-10-11 14:17 UTCEG score recompute
  4. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  7. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  11. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  12. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  13. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  14. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  15. 2026-10-01 16:09 UTCEG score recompute
  16. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  17. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  18. 2026-09-28 13:20 UTCEG score recompute
  19. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  20. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  21. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  22. 2026-09-24 11:46 UTCEG score recompute
  23. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  24. 2026-09-23 06:05 UTCEG score recompute
  25. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
Show 75 more
  1. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  2. 2026-09-18 05:42 UTCEG score recompute
  3. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  4. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  5. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  6. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-09-14 08:13 UTCEG score recompute
  8. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  9. 2026-09-13 08:23 UTCEG score recompute
  10. 2026-09-12 03:30 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  13. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  14. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  15. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  16. 2026-09-05 22:46 UTCEG score recompute
  17. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  18. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  19. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  20. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  22. 2026-08-30 07:28 UTCEG score recompute
  23. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  24. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  25. 2026-08-27 21:49 UTCEG score recompute
  26. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  27. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  28. 2026-08-26 04:47 UTCEG score recompute
  29. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  30. 2026-08-25 00:34 UTCEG score recompute
  31. 2026-08-23 01:06 UTCEG score recompute
  32. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  33. 2026-08-22 01:23 UTCEG score recompute
  34. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  35. 2026-08-21 01:40 UTCEG score recompute
  36. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  37. 2026-08-20 01:57 UTCEG score recompute
  38. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  39. 2026-08-18 20:44 UTCEG score recompute
  40. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  41. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  42. 2026-08-17 12:42 UTCEG score recompute
  43. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  44. 2026-08-16 12:59 UTCEG score recompute
  45. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  46. 2026-08-15 13:16 UTCEG score recompute
  47. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  48. 2026-08-14 13:32 UTCEG score recompute
  49. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  50. 2026-08-12 14:05 UTCEG score recompute
  51. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  52. 2026-08-11 14:17 UTCEG score recompute
  53. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  54. 2026-08-09 14:51 UTCEG score recompute
  55. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  56. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  57. 2026-08-08 15:09 UTCEG score recompute
  58. 2026-08-06 15:43 UTCEG score recompute
  59. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  60. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  61. 2026-08-05 15:52 UTCEG score recompute
  62. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  63. 2026-08-04 13:41 UTCEG score recompute
  64. 2026-08-04 10:39 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  65. 2026-08-02 11:23 UTCEG score recompute
  66. 2026-08-02 02:27 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  67. 2026-08-01 11:40 UTCEG score recompute
  68. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  69. 2026-07-31 11:57 UTCEG score recompute
  70. 2026-07-30 16:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  71. 2026-07-30 12:14 UTCEG score recompute
  72. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  73. 2026-07-29 12:04 UTCEG score recompute
  74. 2026-07-28 15:37 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  75. 2026-07-28 12:21 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-54590?
CVE-2026-54590 is a medium-severity vulnerability; its CVE record was published on July 8, 2026. AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig.settokens that blocks /, , and .. before %u substitution in…
When was the CVE record for CVE-2026-54590 published?
The CVE record for CVE-2026-54590 was published on July 8, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 10, 2026; the record at its source may have been updated since.
Is CVE-2026-54590 actively exploited?
CVE-2026-54590 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54590?
CVE-2026-54590 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54590?
A fix for CVE-2026-54590 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-54590 are linked in the Vendor Advisories panel on this page.

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