CVE-2026-81028

MEDIUMPre-NVD 4.94.9
EchelonGraph scoreMEDIUM confidence

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

Score 4.9 from GitHub Security Advisory (severity: MODERATE) published 2026-08-26. A secondary CVSS source baseline 4.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-66604 (ENISA EUVD) · GHSA-4j5x-jgmh-j582 (GitHub Security Advisories)Source: ENISA EUVD

4.9EG
EchelonGraph verdictMonitorNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 4.9Exploit: None knownExposed services: Not assessed

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

ZLMediaKit confines the downloadFile API to a configured set of root directories with a prefix comparison that does not account for directory boundaries. The configuration loader in server/WebApi.cpp builds each root with File::absolutePath("", item, true); because the relative-path argument is empty that helper returns the value without a trailing separator. The handler then accepts a requested path when start_with(file_path, root) holds, so a sibling directory whose name merely begins with the configured root string satisfies the test and is served. The only other guard rejects a path containing two dots, which this requires none of. The equivalent confinement check for the ordinary static file server in src/Http/HttpFileManager.cpp computes its root with a non-empty second argument, which appends the separator before comparing, and so is not affected. The endpoint requires the configured API secret, so this grants no privilege beyond what that secret already implies, but it reads files outside the directory the operator confined it to, and the reference container runs the server as root.

CVSS v3
4.9
EG Score
4.9MEDIUMmedium confidence
EG Risk
22
EG Risk 22/100

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)
Severity49% × 45%
Impact severity (EG Severity): CVSS 4.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.5%
EPSS %ILE
44th
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 (4.9): severity, escalated by confirmed exploitation. This CVE's 4.9 is its impact severity (EG Severity), not escalated.

EG Severity
4.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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 every mission impact level.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

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.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: 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 26, 2026

Last Modified

October 27, 2026

Advisory Details (4)

Auto-updated Aug 26, 2026
No fix on record yet.
Web page

ZLMediaKit downloadFile Root-Directory Confinement Bypass via Prefix Collision | Advisories | VulnCheck

https://www.vulncheck.com/advisories/zlmediakit-downloadfile-root-directory-confinement-bypass-via-prefix-collision
Web page

ZLMediaKit/server/WebApi.cpp at fa347d7dbe48dfdce525d3a0fdb92e576970ef9f · ZLMediaKit/ZLMediaKit · GitHub

https://github.com/ZLMediaKit/ZLMediaKit/blob/fa347d7dbe48dfdce525d3a0fdb92e576970ef9f/server/WebApi.cpp
Web page

[BUG] downloadFile API root-directory confinement bypass via directory-name prefix collision · Issue #4817 · ZLMediaKit/ZLMediaKit · GitHub

https://github.com/ZLMediaKit/ZLMediaKit/issues/4817
Web page

GitHub - ZLMediaKit/ZLMediaKit: WebRTC/RTSP/RTMP/HTTP/HLS/HTTP-FLV/WebSocket-FLV/HTTP-TS/HTTP-fMP4/WebSocket-TS/WebSocket-fMP4/GB28181/SRT/STUN/TURN server and client framework based on C++11 · GitHub

https://github.com/ZLMediaKit/ZLMediaKit

Vendor Advisories for CVE-2026-81028(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 8× in last 7d / 35× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 180 rows 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 80 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  2. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  3. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  5. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  6. 2026-11-07 19:17 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub severity MODERATE · GitHub CVSS 4.9
  7. 2026-11-07 19:17 UTCEchelonGraph re-scored
  8. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  9. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  10. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  11. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  15. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  16. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-10-29 17:06 UTCEchelonGraph re-scored
  18. 2026-10-29 17:06 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  19. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  20. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  22. 2026-10-27 11:26 UTCEchelonGraph re-scored
  23. 2026-10-27 11:26 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  24. 2026-10-27 10:25 UTCEchelonGraph re-scored
  25. 2026-10-27 10:25 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
Show 75 more
  1. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  2. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  3. 2026-10-25 13:58 UTCEchelonGraph re-scored
  4. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  6. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-10-22 13:53 UTCEchelonGraph re-scored
  8. 2026-10-22 13:53 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  9. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-10-18 03:09 UTCEchelonGraph re-scored
  14. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  17. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  19. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-10-12 14:57 UTCEchelonGraph re-scored
  21. 2026-10-11 19:21 UTCEchelonGraph re-scored
  22. 2026-10-11 16:37 UTCEchelonGraph re-scored
  23. 2026-10-11 13:55 UTCEchelonGraph re-scored
  24. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  25. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-10-10 06:06 UTCEchelonGraph re-scored
  27. 2026-10-10 06:06 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  28. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  29. 2026-10-09 03:22 UTCEchelonGraph re-scored
  30. 2026-10-09 03:22 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  31. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  32. 2026-10-08 01:50 UTCEchelonGraph re-scored
  33. 2026-10-08 01:49 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  34. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  35. 2026-10-07 01:17 UTCEchelonGraph re-scored
  36. 2026-10-07 01:17 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  37. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  38. 2026-10-06 02:31 UTCEchelonGraph re-scored
  39. 2026-10-06 02:31 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  40. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  41. 2026-10-05 03:44 UTCEchelonGraph re-scored
  42. 2026-10-05 03:44 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  43. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  44. 2026-10-04 04:01 UTCEchelonGraph re-scored
  45. 2026-10-04 04:01 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  46. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  47. 2026-10-03 05:07 UTCEchelonGraph re-scored
  48. 2026-10-03 05:07 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  49. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  50. 2026-10-02 06:21 UTCEchelonGraph re-scored
  51. 2026-10-02 06:21 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  52. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  53. 2026-10-01 05:32 UTCEchelonGraph re-scored
  54. 2026-10-01 05:32 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  55. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  56. 2026-09-30 06:03 UTCEchelonGraph re-scored
  57. 2026-09-30 06:03 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  58. 2026-09-28 21:20 UTCEchelonGraph re-scored
  59. 2026-09-28 21:20 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  60. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  61. 2026-09-27 19:29 UTCEchelonGraph re-scored
  62. 2026-09-27 19:29 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  63. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  64. 2026-09-26 20:35 UTCEchelonGraph re-scored
  65. 2026-09-26 20:35 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  66. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  67. 2026-09-25 15:48 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  68. 2026-09-24 16:12 UTCEchelonGraph re-scored
  69. 2026-09-24 16:12 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  70. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  71. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  72. 2026-09-23 17:26 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  73. 2026-09-23 13:37 UTCEchelonGraph re-scored
  74. 2026-09-23 13:37 UTCGHSA enrichmentGHSA-4j5x-jgmh-j582 · GitHub CVSS 4.9
  75. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.4% · 28th percentile

Frequently asked(5)

What is CVE-2026-81028?
CVE-2026-81028 is a medium-severity vulnerability; its CVE record was published on August 26, 2026. ZLMediaKit confines the downloadFile API to a configured set of root directories with a prefix comparison that does not account for directory boundaries. The configuration loader in server/WebApi.cpp builds each root with File::absolutePath("", item, true); because the relative-path argument is…
When was CVE-2026-81028 made public?
CVE-2026-81028 was made public on August 26, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 26, 2026. EchelonGraph's copy of the record carries a last-modified date of October 27, 2026; the record at its source may have been updated since.
Is CVE-2026-81028 actively exploited?
CVE-2026-81028 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (44th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81028?
CVE-2026-81028 has a CVSS base score of 4.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81028?
No fix for CVE-2026-81028 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-2026-81028 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-81028

Explore →

Is Your Infrastructure Affected by CVE-2026-81028?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.