CVE-2026-38821

HIGHPre-NVD 7.17.1
EchelonGraph scoreMEDIUM confidence

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

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-08-28. A secondary CVSS source baseline 7.1; 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
7.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A heap-based buffer overflow vulnerability exists in openNDS before 11.0.0 that allows an unauthenticated attacker on the captive portal network to crash the openNDS daemon (denial of service) and potentially achieve remote code execution. This is in http_microhttpd.c.

CVSS v3
7.1
EG Score
7.1HIGHmedium confidence
EG Risk
32
EG Risk 32/100

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)
Severity71% × 45%
Impact severity (EG Severity): CVSS 7.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
22nd
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 (7.1): severity, escalated by confirmed exploitation. This CVE's 7.1 is its impact severity (EG Severity), not escalated.

EG Severity
7.1 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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 low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

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 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 28, 2026

Last Modified

September 9, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
Patch available. Sources: github_commit.
GitHub commit Patch Available

commit 3b5f7ef40cd0 (openNDS/openNDS)

Patch available: openNDS/openNDS v11.0.0 (contains commit 3b5f7ef40cd0)

https://github.com/openNDS/openNDS/commit/3b5f7ef40cd048826d3c4a16f61a73a1768fd5a9

Vendor Advisories for CVE-2026-38821(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
opennds10.2.0+dfsg-1, 10.3.0+dfsg-0.1, 10.3.1+dfsg-1, 9.10.0-1
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
opennds10.3.1+dfsg-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
opennds10.3.1+dfsg-1
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 89× 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 186 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 87 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  2. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  3. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-10-18 03:44 UTCEG score recompute
  5. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-10-17 15:09 UTCEG score recompute
  7. 2026-10-17 15:08 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  8. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  13. 2026-10-12 16:10 UTCEG score recompute
  14. 2026-10-11 19:52 UTCEG score recompute
  15. 2026-10-11 17:06 UTCEG score recompute
  16. 2026-10-11 14:32 UTCEG score recompute
  17. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  18. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-10-10 13:07 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  20. 2026-10-10 01:26 UTCEG score recompute
  21. 2026-10-10 01:25 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  22. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  23. 2026-10-09 02:49 UTCEG score recompute
  24. 2026-10-09 02:49 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  25. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
Show 74 more
  1. 2026-10-08 01:03 UTCEG score recompute
  2. 2026-10-08 01:03 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  3. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-10-07 07:05 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  5. 2026-10-06 19:13 UTCEG score recompute
  6. 2026-10-06 19:13 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  7. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-10-06 07:29 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  9. 2026-10-05 19:03 UTCEG score recompute
  10. 2026-10-05 19:03 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  11. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-10-05 07:19 UTCEG score recompute
  13. 2026-10-05 07:19 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  15. 2026-10-04 19:37 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  16. 2026-10-04 07:02 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  17. 2026-10-03 19:20 UTCEG score recompute
  18. 2026-10-03 19:20 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  19. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  20. 2026-10-03 06:59 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  21. 2026-10-02 19:17 UTCEG score recompute
  22. 2026-10-02 19:17 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  23. 2026-10-02 07:32 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  24. 2026-10-01 19:50 UTCEG score recompute
  25. 2026-10-01 19:50 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  26. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  27. 2026-10-01 07:33 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  28. 2026-09-30 19:52 UTCEG score recompute
  29. 2026-09-30 19:52 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  30. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  31. 2026-09-30 04:00 UTCEG score recompute
  32. 2026-09-30 04:00 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  33. 2026-09-29 14:14 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  34. 2026-09-29 02:32 UTCEG score recompute
  35. 2026-09-29 02:32 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  36. 2026-09-28 14:50 UTCEG score recompute
  37. 2026-09-28 14:50 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  38. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  39. 2026-09-28 03:08 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  40. 2026-09-27 15:26 UTCEG score recompute
  41. 2026-09-27 15:26 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  42. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  43. 2026-09-27 03:24 UTCEG score recompute
  44. 2026-09-27 03:24 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  45. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  46. 2026-09-26 15:41 UTCEG score recompute
  47. 2026-09-26 15:41 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  48. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  49. 2026-09-25 07:31 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  50. 2026-09-24 19:49 UTCEG score recompute
  51. 2026-09-24 19:49 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  52. 2026-09-24 08:07 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  53. 2026-09-23 20:25 UTCEG score recompute
  54. 2026-09-23 20:25 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  55. 2026-09-23 08:43 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  56. 2026-09-22 21:01 UTCEG score recompute
  57. 2026-09-22 21:01 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  58. 2026-09-22 09:19 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  59. 2026-09-21 21:36 UTCEG score recompute
  60. 2026-09-21 21:36 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  61. 2026-09-21 09:54 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  62. 2026-09-20 22:13 UTCEG score recompute
  63. 2026-09-20 22:13 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  64. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  65. 2026-09-20 10:30 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  66. 2026-09-19 22:48 UTCEG score recompute
  67. 2026-09-19 22:48 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  68. 2026-09-19 11:06 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  69. 2026-09-18 23:24 UTCEG score recompute
  70. 2026-09-18 23:24 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  71. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  72. 2026-09-18 11:43 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1
  73. 2026-09-18 00:01 UTCEG score recompute
  74. 2026-09-18 00:01 UTCGHSA enrichmentGHSA-rm65-3jj4-3vcm · GitHub severity HIGH · GitHub CVSS 7.1

Frequently asked(5)

What is CVE-2026-38821?
CVE-2026-38821 is a high-severity vulnerability; its CVE record was published on August 28, 2026. A heap-based buffer overflow vulnerability exists in openNDS before 11.0.0 that allows an unauthenticated attacker on the captive portal network to crash the openNDS daemon (denial of service) and potentially achieve remote code execution. This is in http_microhttpd.c.
When was the CVE record for CVE-2026-38821 published?
The CVE record for CVE-2026-38821 was published on August 28, 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 9, 2026; the record at its source may have been updated since.
Is CVE-2026-38821 actively exploited?
CVE-2026-38821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (22nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-38821?
CVE-2026-38821 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-38821?
A fix for CVE-2026-38821 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-38821 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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