CVE-2026-66729

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-27. A secondary CVSS source baseline 7.5; 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 weekElevated
7.5EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

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

The CVE record's CNA (VulnCheck) lists boazsegev facil.io versions 0.6.0 up to and including 0.7.6 as affected. No release containing a fix is confirmed on record.

facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an empty field name. Attackers can trigger a uint32_t wraparound in http_mime_parser.h causing an out-of-bounds memory read past the name pointer, resulting in a bus fault that crashes the handling worker with a single POST request.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.8%
EPSS %ILE
55th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.8% 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; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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; Attend 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 at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

July 27, 2026

Last Modified

July 31, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
No fix on record yet.
Web page

facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart MIME Body Parser | Advisories | VulnCheck

https://www.vulncheck.com/advisories/facil-io-integer-underflow-dos-via-multipart-mime-body-parser
Web page

GitHub - theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-Server-Crash: Security Advisory: Out-of-Bounds Read in facil.io MIME Parser leads to Server crash · GitHub

https://github.com/theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-Server-Crash

Vendor Advisories for CVE-2026-66729(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 10× in last 7d / 53× 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 248 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 148 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  2. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  3. 2026-10-18 03:20 UTCEG score recompute
  4. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  5. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  6. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  7. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  8. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  9. 2026-10-13 10:53 UTCEG score recompute
  10. 2026-10-13 10:53 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  11. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  12. 2026-10-12 15:46 UTCEG score recompute
  13. 2026-10-11 19:31 UTCEG score recompute
  14. 2026-10-11 16:46 UTCEG score recompute
  15. 2026-10-11 14:07 UTCEG score recompute
  16. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  17. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  18. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  19. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  20. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  21. 2026-10-07 02:27 UTCEG score recompute
  22. 2026-10-07 02:27 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  25. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.8% · 54th percentile
Show 75 more
  1. 2026-10-04 07:18 UTCEG score recompute
  2. 2026-10-04 07:18 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  3. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  4. 2026-10-02 18:27 UTCEG score recompute
  5. 2026-10-02 18:27 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  6. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  7. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  8. 2026-10-01 14:48 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  9. 2026-10-01 03:52 UTCEG score recompute
  10. 2026-10-01 03:52 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  11. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  12. 2026-09-29 07:53 UTCEG score recompute
  13. 2026-09-29 07:53 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  14. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  15. 2026-09-28 03:34 UTCEG score recompute
  16. 2026-09-28 03:33 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  18. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  19. 2026-09-25 06:52 UTCEG score recompute
  20. 2026-09-25 06:52 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  21. 2026-09-24 08:58 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  22. 2026-09-23 22:02 UTCEG score recompute
  23. 2026-09-23 22:02 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  24. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-09-23 08:44 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  26. 2026-09-22 21:48 UTCEG score recompute
  27. 2026-09-22 21:48 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  28. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  29. 2026-09-20 00:55 UTCEG score recompute
  30. 2026-09-20 00:55 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  31. 2026-09-19 08:17 UTCEG score recompute
  32. 2026-09-19 08:17 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  33. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  34. 2026-09-18 18:53 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  35. 2026-09-18 02:23 UTCEG score recompute
  36. 2026-09-18 02:23 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  37. 2026-09-17 01:46 UTCEG score recompute
  38. 2026-09-17 01:46 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  39. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  40. 2026-09-16 06:16 UTCEG score recompute
  41. 2026-09-16 06:16 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  42. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-09-15 09:08 UTCEG score recompute
  44. 2026-09-15 09:08 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-09-14 12:17 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-09-14 01:22 UTCEG score recompute
  47. 2026-09-14 01:22 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-09-13 14:26 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  49. 2026-09-13 03:30 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  50. 2026-09-12 16:34 UTCEG score recompute
  51. 2026-09-12 16:34 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  52. 2026-09-12 05:37 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-09-11 18:41 UTCEG score recompute
  54. 2026-09-11 18:41 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  55. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  56. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  57. 2026-09-11 07:45 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  58. 2026-09-10 20:48 UTCEG score recompute
  59. 2026-09-10 20:48 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  60. 2026-09-10 08:14 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  61. 2026-09-09 08:19 UTCEG score recompute
  62. 2026-09-09 08:19 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  63. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  64. 2026-09-07 21:03 UTCEG score recompute
  65. 2026-09-07 21:03 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  67. 2026-09-06 18:37 UTCEG score recompute
  68. 2026-09-06 18:37 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  70. 2026-09-06 07:41 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  71. 2026-09-05 19:15 UTCEG score recompute
  72. 2026-09-05 19:15 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5
  73. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  74. 2026-09-05 05:45 UTCEG score recompute
  75. 2026-09-05 05:45 UTCGHSA enrichmentGHSA-g2qx-6r8w-37px · GitHub severity HIGH · GitHub CVSS 7.5

Frequently asked(5)

What is CVE-2026-66729?
CVE-2026-66729 is a high-severity vulnerability; its CVE record was published on July 27, 2026. facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an empty field name. Attackers can trigger a uint32t wraparound in…
When was CVE-2026-66729 made public?
CVE-2026-66729 was made public on July 24, 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 July 27, 2026. EchelonGraph's copy of the record carries a last-modified date of July 31, 2026; the record at its source may have been updated since.
Is CVE-2026-66729 actively exploited?
CVE-2026-66729 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (55th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66729?
CVE-2026-66729 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66729?
No fix for CVE-2026-66729 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 CVE record's CNA (VulnCheck) lists boazsegev facil.io versions 0.6.0 up to and including 0.7.6 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-66729 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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