CVE-2026-77763

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-21. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.5Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

The filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync destination, derived every operation's target from path(key), which returned either filepath.Join(d.root, key) or filepath.Clean(d.root + key) with no check that the result stayed beneath the root. Put, Get, Head, Delete, Chmod, Chown, Symlink and Readlink all consumed that value directly. Object keys enumerated from a source object store during a sync are not constrained the way local filesystem names are, so a key containing traversal segments causes juicefs to write attacker-supplied content to a path outside the intended local destination, and no error is returned. An operator syncing from a bucket whose contents they do not fully control, such as a shared or public bucket or one an attacker can write to, is therefore exposed to a file write at an attacker-influenced location. The fix changes path() to return an error and rejects any key whose resolved path escapes the root.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

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)
Severity65% × 45%
The EG Score, 6.5 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 every mission impact level.
Exploitation none (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: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
EPSS PROB
0.5%
EPSS %ILE
40th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.

Exploitation none (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

August 21, 2026

Last Modified

September 24, 2026

Advisory Details (6)

Auto-updated Aug 21, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

JuiceFS Local Filestore Backend Joins Object Keys onto the Storage Root Without a Containment Check, Allowing Writes Outside the Configured Directory | Advisories | VulnCheck

https://www.vulncheck.com/advisories/juicefs-local-filestore-backend-joins-object-keys-onto-the-storage-root-without-a-containment-check-allowing-writes-outside-the-configured-directory
github_pr

object/file: reject object keys that escape the filestore root

Fix merged in juicedata/juicefs PR #7425 on 2026-08-21 — awaiting tagged release

https://github.com/juicedata/juicefs/pull/7425
generic

Local filestore object backend writes outside its configured root via a crafted object key · Issue #7401 · juicedata/juicefs · GitHub

https://github.com/juicedata/juicefs/issues/7401
github_commit

commit 0bcd70b3d130 (juicedata/juicefs)

Fix landed in juicedata/juicefs commit 0bcd70b3d130 — awaiting tagged release

https://github.com/juicedata/juicefs/commit/0bcd70b3d13088d38127d6fb5750c91be7c4ec16
generic

juicefs/pkg/object/file.go at v1.4.1 · juicedata/juicefs · GitHub

https://github.com/juicedata/juicefs/blob/v1.4.1/pkg/object/file.go
generic

GitHub - juicedata/juicefs: JuiceFS is a distributed POSIX file system built on top of Redis and S3. · GitHub

https://github.com/juicedata/juicefs

Vendor Advisories for CVE-2026-77763(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 18× in last 7d / 77× 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 99 of 137 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 38 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 13:57 UTCEG score recompute
  2. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-09 06:01 UTCEG score recompute
  6. 2026-10-09 06:01 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  7. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-10-08 04:58 UTCEG score recompute
  9. 2026-10-08 04:58 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  10. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  11. 2026-10-06 21:18 UTCEG score recompute
  12. 2026-10-06 21:18 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  14. 2026-10-05 20:52 UTCEG score recompute
  15. 2026-10-05 20:52 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  18. 2026-10-04 20:49 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  19. 2026-10-03 16:43 UTCEG score recompute
  20. 2026-10-03 16:43 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  21. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  22. 2026-10-02 08:04 UTCEG score recompute
  23. 2026-10-02 08:04 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  25. 2026-10-01 08:01 UTCEG score recompute
Show 74 more
  1. 2026-10-01 08:01 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  2. 2026-09-30 07:57 UTCEG score recompute
  3. 2026-09-30 07:57 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  4. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-09-29 02:42 UTCEG score recompute
  6. 2026-09-29 02:42 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  7. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-09-28 02:38 UTCEG score recompute
  9. 2026-09-28 02:38 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  10. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  11. 2026-09-27 02:32 UTCEG score recompute
  12. 2026-09-27 02:32 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  13. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  14. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  15. 2026-09-24 21:21 UTCEG score recompute
  16. 2026-09-24 21:21 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  17. 2026-09-24 14:58 UTCEG score recompute
  18. 2026-09-24 14:58 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  19. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  20. 2026-09-24 03:57 UTCEG score recompute
  21. 2026-09-24 03:57 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  22. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  23. 2026-09-23 03:51 UTCEG score recompute
  24. 2026-09-23 03:51 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  25. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  26. 2026-09-22 03:47 UTCEG score recompute
  27. 2026-09-22 03:47 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  28. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  29. 2026-09-21 03:42 UTCEG score recompute
  30. 2026-09-21 03:42 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  31. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  32. 2026-09-20 03:38 UTCEG score recompute
  33. 2026-09-20 03:38 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  34. 2026-09-19 03:34 UTCEG score recompute
  35. 2026-09-19 03:34 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  36. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  37. 2026-09-18 03:31 UTCEG score recompute
  38. 2026-09-18 03:31 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  39. 2026-09-17 03:27 UTCEG score recompute
  40. 2026-09-17 03:27 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  41. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  42. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  43. 2026-09-16 03:03 UTCEG score recompute
  44. 2026-09-16 03:03 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  45. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  46. 2026-09-15 02:59 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  47. 2026-09-14 02:56 UTCEG score recompute
  48. 2026-09-14 02:56 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  49. 2026-09-13 02:53 UTCEG score recompute
  50. 2026-09-13 02:53 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  51. 2026-09-12 02:49 UTCEG score recompute
  52. 2026-09-12 02:49 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  53. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  54. 2026-09-11 02:45 UTCEG score recompute
  55. 2026-09-11 02:45 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  56. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  57. 2026-09-10 02:41 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  58. 2026-09-09 02:37 UTCEG score recompute
  59. 2026-09-09 02:37 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  60. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  61. 2026-09-08 02:34 UTCEG score recompute
  62. 2026-09-08 02:34 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  63. 2026-09-07 02:30 UTCEG score recompute
  64. 2026-09-07 02:29 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  65. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  66. 2026-09-06 01:47 UTCEG score recompute
  67. 2026-09-06 01:47 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  68. 2026-09-05 01:44 UTCEG score recompute
  69. 2026-09-05 01:44 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  70. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  71. 2026-09-04 01:40 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  72. 2026-09-03 01:37 UTCEG score recompute
  73. 2026-09-03 01:36 UTCGHSA enrichmentGHSA-2pgv-c2r7-f43r · GitHub severity HIGH · GitHub CVSS 6.5
  74. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 25th percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77763?
CVE-2026-77763 is a medium-severity vulnerability; its CVE record was published on August 21, 2026. The filestore backend in pkg/object/file.go, used for file:// stores and as a common juicefs sync destination, derived every operation's target from path(key), which returned either filepath.Join(d.root, key) or filepath.Clean(d.root + key) with no check that the result stayed beneath the root.…
When was the CVE record for CVE-2026-77763 published?
The CVE record for CVE-2026-77763 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 September 24, 2026; the record at its source may have been updated since.
Is CVE-2026-77763 actively exploited?
CVE-2026-77763 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77763?
CVE-2026-77763 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77763?
An upstream fix for CVE-2026-77763 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-77763 are linked in the Vendor Advisories panel on this page.

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