CVE-2026-77086

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-21. The CNA's CVSS baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 9.1Exploit: None knownExposed services: Not assessed

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

SiYuan before v3.7.4 fails to validate the packageName parameter in Bazaar install and uninstall endpoints, allowing authenticated administrators to perform path traversal via directory traversal sequences. Attackers with admin access can write arbitrary files to any location via install operations or recursively delete directories via uninstall operations by supplying crafted packageName values.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
41
EG Risk 41/100

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)
Severity91% × 45%
The EG Score, 9.1 of 10.
Exploitation1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
1.0%
EPSS %ILE
62nd
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* 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, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

August 21, 2026

Last Modified

October 1, 2026

Advisory Details (2)

Auto-updated Sep 15, 2026
No fix on record yet. Sources: github.
generic

SiYuan before v3.7.4 Path Traversal via packageName | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-path-traversal-via-packagename
githubMentions a patch (unverified)

Path Traversal via unvalidated packageName across all 10 Bazaar install/uninstall endpoints, enabling arbitrary-location file write (install) and arbitrary recursive directory deletion (uninstall) · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-wr4w-7vjm-mmx3

Vendor Advisories for CVE-2026-77086(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 31× in last 7d / 192× 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 359 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 259 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 13:58 UTCEG score recompute
  2. 2026-10-11 13:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  3. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  4. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  5. 2026-10-09 06:01 UTCEG score recompute
  6. 2026-10-09 06:01 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-10-08 17:13 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  8. 2026-10-08 08:51 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  9. 2026-10-08 04:58 UTCEG score recompute
  10. 2026-10-08 04:58 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  12. 2026-10-07 09:11 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  13. 2026-10-07 05:13 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-10-07 01:14 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  15. 2026-10-06 21:18 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  16. 2026-10-06 16:50 UTCEG score recompute
  17. 2026-10-06 16:50 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  18. 2026-10-06 15:18 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  19. 2026-10-06 12:14 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  20. 2026-10-06 07:49 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  21. 2026-10-06 03:06 UTCEG score recompute
  22. 2026-10-06 03:06 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  23. 2026-10-05 17:43 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-10-05 17:42 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  25. 2026-10-05 13:51 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
Show 75 more
  1. 2026-10-05 09:26 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  2. 2026-10-05 05:24 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  3. 2026-10-05 01:32 UTCEG score recompute
  4. 2026-10-05 01:32 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  5. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  6. 2026-10-04 20:49 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-10-04 14:41 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  8. 2026-10-04 10:15 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  9. 2026-10-04 06:22 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-10-04 02:31 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  11. 2026-10-03 20:47 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  12. 2026-10-03 16:43 UTCEG score recompute
  13. 2026-10-03 16:43 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-10-03 14:26 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  15. 2026-10-03 04:34 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  16. 2026-10-03 00:39 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  17. 2026-10-02 18:54 UTCEG score recompute
  18. 2026-10-02 18:54 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  19. 2026-10-02 14:56 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  20. 2026-10-02 11:04 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  21. 2026-10-02 06:46 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  22. 2026-10-02 01:20 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  23. 2026-10-01 21:25 UTCEG score recompute
  24. 2026-10-01 21:25 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  25. 2026-10-01 19:50 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  26. 2026-10-01 15:28 UTCEG score recompute
  27. 2026-10-01 15:28 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  28. 2026-10-01 13:23 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  29. 2026-10-01 09:31 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  30. 2026-10-01 05:40 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  31. 2026-10-01 01:10 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  32. 2026-09-30 20:29 UTCEG score recompute
  33. 2026-09-30 20:29 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  34. 2026-09-30 11:54 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  35. 2026-09-30 07:58 UTCEG score recompute
  36. 2026-09-30 07:58 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  37. 2026-09-29 15:24 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  38. 2026-09-29 05:40 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  39. 2026-09-29 01:48 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  40. 2026-09-28 21:36 UTCEG score recompute
  41. 2026-09-28 21:36 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  42. 2026-09-28 15:58 UTCEG score recompute
  43. 2026-09-28 15:58 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  44. 2026-09-28 13:52 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  45. 2026-09-28 11:34 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  46. 2026-09-28 07:42 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  47. 2026-09-28 03:50 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  48. 2026-09-27 23:56 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  49. 2026-09-27 19:53 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  50. 2026-09-27 15:48 UTCEG score recompute
  51. 2026-09-27 15:48 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  52. 2026-09-27 13:48 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  53. 2026-09-27 10:59 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  54. 2026-09-27 06:50 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  55. 2026-09-27 02:32 UTCEG score recompute
  56. 2026-09-27 02:32 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  57. 2026-09-26 15:59 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  58. 2026-09-26 00:28 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  59. 2026-09-25 17:14 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  60. 2026-09-25 12:17 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  61. 2026-09-25 08:24 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  62. 2026-09-25 04:28 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  63. 2026-09-25 00:36 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  64. 2026-09-24 19:30 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  65. 2026-09-24 15:38 UTCEG score recompute
  66. 2026-09-24 15:38 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  67. 2026-09-24 14:04 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  68. 2026-09-24 11:41 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  69. 2026-09-24 07:49 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  70. 2026-09-24 03:57 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  71. 2026-09-23 23:53 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  72. 2026-09-23 20:02 UTCEG score recompute
  73. 2026-09-23 20:02 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1
  74. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  75. 2026-09-23 15:12 UTCGHSA enrichmentGHSA-w7g2-952j-gmgr · GitHub severity CRITICAL · GitHub CVSS 9.1

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77086?
CVE-2026-77086 is a critical-severity vulnerability; its CVE record was published on August 21, 2026. SiYuan before v3.7.4 fails to validate the packageName parameter in Bazaar install and uninstall endpoints, allowing authenticated administrators to perform path traversal via directory traversal sequences. Attackers with admin access can write arbitrary files to any location via install operations…
When was the CVE record for CVE-2026-77086 published?
The CVE record for CVE-2026-77086 was published on August 21, 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 October 1, 2026; the record at its source may have been updated since.
Is CVE-2026-77086 actively exploited?
CVE-2026-77086 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (62nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77086?
CVE-2026-77086 has a CVSS base score of 9.1 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-77086?
No fix for CVE-2026-77086 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-2026-77086 are linked in the Vendor Advisories panel on this page.

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