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 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
Trending — 3 sources updated this week
4.9EG
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: 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 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)
Severity49% × 45%
The EG Score, 4.9 of 10.
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. 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
0.5%
EPSS %ILE
42nd
KEV
Not listed

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

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 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 26, 2026

Last Modified

September 23, 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 17× in last 7d / 80× 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 98 of 136 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. 2 repeat rows among the latest 100 are merged into the row they repeat. The 38 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

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

Related CVEs(same CWE)

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 September 23, 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 (42nd 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

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