CVE-2026-66754

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

Score 5.9 from GitHub Security Advisory (severity: HIGH) published 2026-07-28. A secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
5.9EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (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: 0.6%CVSS: 5.9Exploit: 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.

Rouille 0.1.6 through 3.6.2 contains a reachable assertion vulnerability in the Request::remove_prefix function that allows remote unauthenticated attackers to crash the server by sending a crafted percent-encoded URL. Attackers can send a request whose decoded path matches a configured prefix while the raw percent-encoded path does not, causing the assert! to fail and triggering either a 500 error or full process termination depending on the panic configuration.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
43
EG Risk 43/100

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)
Severity59% × 45%
The EG Score, 5.9 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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 public PoC (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
0.6%
EPSS %ILE
45th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* 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, and watch the vendor's advisory for the fix.

Exploitation public PoC (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

July 28, 2026

Last Modified

July 30, 2026

Advisory Details (2)

Auto-updated Jul 28, 2026
No fix on record yet.
generic

Rouille 0.1.6 - 3.6.2 Reachable Assertion DoS via remove_prefix percent-encoding | Advisories | VulnCheck

https://www.vulncheck.com/advisories/rouille-reachable-assertion-dos-via-remove-prefix-percent-encoding
generic

GitHub - theopaid/Remote-Denial-of-Service-via-Reachable-Assertion-in-URL-Prefix-Handling-rouille-: Security Advisory: Remote Denial of Service via Reachable Assertion in URL Prefix Handling (rouille) · GitHub

https://github.com/theopaid/Remote-Denial-of-Service-via-Reachable-Assertion-in-URL-Prefix-Handling-rouille-

Vendor Advisories for CVE-2026-66754(1)

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

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
rust-rouille3.6.2+20250617+ds-1, 3.6.2+20250617+ds-2, 3.6.2+20250617+ds-3
  • 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 11× in last 7d / 56× 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 170 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 70 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 14:07 UTCEG score recompute
  2. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  3. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  4. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  5. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  6. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  7. 2026-10-07 00:05 UTCEG score recompute
  8. 2026-10-07 00:05 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  9. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  10. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  11. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  12. 2026-10-04 07:09 UTCEG score recompute
  13. 2026-10-04 07:09 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  14. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  15. 2026-10-02 18:24 UTCEG score recompute
  16. 2026-10-02 18:24 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  17. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  18. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  19. 2026-10-01 03:43 UTCEG score recompute
  20. 2026-10-01 03:43 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  22. 2026-09-29 07:46 UTCEG score recompute
  23. 2026-09-29 07:46 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  24. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  25. 2026-09-28 03:23 UTCEG score recompute
Show 75 more
  1. 2026-09-28 03:23 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  2. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  3. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  4. 2026-09-25 06:13 UTCEG score recompute
  5. 2026-09-25 06:13 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  6. 2026-09-24 00:18 UTCEG score recompute
  7. 2026-09-24 00:18 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  8. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  9. 2026-09-22 21:41 UTCEG score recompute
  10. 2026-09-22 21:41 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  11. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  12. 2026-09-20 11:19 UTCEG score recompute
  13. 2026-09-20 11:19 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  14. 2026-09-19 05:16 UTCEG score recompute
  15. 2026-09-19 05:16 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  16. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  17. 2026-09-18 02:06 UTCEG score recompute
  18. 2026-09-18 02:06 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  19. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  20. 2026-09-16 11:50 UTCEG score recompute
  21. 2026-09-16 11:50 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  22. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  23. 2026-09-15 08:39 UTCEG score recompute
  24. 2026-09-15 08:39 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  25. 2026-09-13 20:20 UTCEG score recompute
  26. 2026-09-13 20:20 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  27. 2026-09-12 17:45 UTCEG score recompute
  28. 2026-09-12 17:45 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  29. 2026-09-11 15:22 UTCEG score recompute
  30. 2026-09-11 15:22 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  31. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  32. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  33. 2026-09-10 10:24 UTCEG score recompute
  34. 2026-09-10 10:24 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  35. 2026-09-09 08:02 UTCEG score recompute
  36. 2026-09-09 08:02 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  37. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  38. 2026-09-08 01:36 UTCEG score recompute
  39. 2026-09-08 01:36 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  40. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  41. 2026-09-06 23:14 UTCEG score recompute
  42. 2026-09-06 23:14 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  43. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  44. 2026-09-05 19:10 UTCEG score recompute
  45. 2026-09-05 19:10 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  46. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  47. 2026-09-04 12:01 UTCEG score recompute
  48. 2026-09-04 12:01 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  49. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  50. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  51. 2026-09-01 22:53 UTCEG score recompute
  52. 2026-09-01 22:53 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  53. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  54. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  55. 2026-08-31 01:55 UTCEG score recompute
  56. 2026-08-31 01:55 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  57. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  58. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  59. 2026-08-29 23:32 UTCEG score recompute
  60. 2026-08-29 23:32 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  61. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  62. 2026-08-27 04:47 UTCEG score recompute
  63. 2026-08-27 04:46 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  64. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  65. 2026-08-26 02:23 UTCEG score recompute
  66. 2026-08-26 02:23 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  67. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  68. 2026-08-25 00:01 UTCEG score recompute
  69. 2026-08-25 00:01 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  70. 2026-08-23 21:38 UTCEG score recompute
  71. 2026-08-23 21:38 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  72. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  73. 2026-08-22 19:16 UTCEG score recompute
  74. 2026-08-22 19:16 UTCGHSA enrichmentGHSA-mrg5-7f6c-r28q · GitHub severity HIGH · GitHub CVSS 5.9
  75. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-66754?
CVE-2026-66754 is a medium-severity vulnerability; its CVE record was published on July 28, 2026. Rouille 0.1.6 through 3.6.2 contains a reachable assertion vulnerability in the Request::remove_prefix function that allows remote unauthenticated attackers to crash the server by sending a crafted percent-encoded URL. Attackers can send a request whose decoded path matches a configured prefix…
When was the CVE record for CVE-2026-66754 published?
The CVE record for CVE-2026-66754 was published on July 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 July 30, 2026; the record at its source may have been updated since.
Is CVE-2026-66754 actively exploited?
CVE-2026-66754 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (45th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66754?
CVE-2026-66754 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66754?
No fix for CVE-2026-66754 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-2026-66754 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-66754

Explore →

Is Your Infrastructure Affected by CVE-2026-66754?

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

Book a Demo →Browse All CVEs