CVE-2026-73548

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (40th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-84103 (ENISA EUVD)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate 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: 0.5%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete HTTP/1.1 request in extended CONNECT data; Envoy downgrades the request, writes the data unframed to a keep-alive HTTP/1.1 upstream, and returns the socket to the shared pool while the smuggled response remains queued. A different downstream client can then receive the attacker's response. The relevant scope boundary is that webSocket upgrades, plain CONNECT, disabled backend keep-alive, per-downstream pools, and max_requests_per_connection set to 1 are not affected by the demonstrated path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
40th
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.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). 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, and whom BOD 26-04 binds: 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).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

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.

The score's inputs: 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

September 21, 2026

Last Modified

October 5, 2026

Advisory Details (9)

Auto-updated Sep 21, 2026
Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

v1.39.1

Patch available: envoyproxy/envoy v1.39.1

https://github.com/envoyproxy/envoy/releases/tag/v1.39.1
GitHub release Patch Available

v1.38.4

Patch available: envoyproxy/envoy v1.38.4

https://github.com/envoyproxy/envoy/releases/tag/v1.38.4
GitHub release Patch Available

v1.37.6

Patch available: envoyproxy/envoy v1.37.6

https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
GitHub release Patch Available

v1.36.10

Patch available: envoyproxy/envoy v1.36.10

https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
GitHub commit

commit bd6711f26176 (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit bd6711f26176 — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/bd6711f2617658e28dfa3df3dace6bfe3cfc0766
GitHub commit

commit 4633b8cce3d1 (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 4633b8cce3d1 — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/4633b8cce3d15b8734eefe232e30c12b0140b91c
GitHub commit

commit 3c7998545a9c (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 3c7998545a9c — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/3c7998545a9c9fb3933a4bc1907d92f0e752bc2b
GitHub commit

commit 309855626966 (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 309855626966 — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/309855626966cff176155c821043ed3b44671361
GitHub advisoryMentions a patch (unverified)

Cross-user response poisoning via a generic (non-WebSocket) HTTP upgrade on Envoy's shared backend pool · Advisory · envoyproxy/envoy · GitHub

Affected: 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the exact releases

https://github.com/envoyproxy/envoy/security/advisories/GHSA-3vhp-c83q-jqc2

Patch Availability(5)

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 68× 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 119 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 19 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

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

Frequently asked(5)

What is CVE-2026-73548?
CVE-2026-73548 is a high-severity vulnerability; its CVE record was published on September 21, 2026. Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete…
When was the CVE record for CVE-2026-73548 published?
The CVE record for CVE-2026-73548 was published on September 21, 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 October 5, 2026; the record at its source may have been updated since.
Is CVE-2026-73548 actively exploited?
CVE-2026-73548 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73548?
CVE-2026-73548 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-2026-73548?
A fix for CVE-2026-73548 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-73548 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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