CVE-2026-73549

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (49th 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

Also known asEUVD-2026-84108 (ENISA EUVD)Source: ENISA EUVD

5.3EG
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: 0.6%CVSS: 5.3Exploit: None knownExposed 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's Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string includes a percent scope identifier that inet_pton cannot parse, causing an exception or abort. Kernel-provided scoped IPv6 destinations in ORIGINAL_DST transparent-proxy deployments, and affected QUIC connection paths, can therefore terminate the process. The relevant scope boundary is that the HTTP use_http_header override rejects scoped addresses earlier; the advisory's crash path requires a kernel-provided original destination or the affected QUIC path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.6%
EPSS %ILE
49th
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-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
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

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.

The score's inputs: 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

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 ab2dca2d65b0 (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit ab2dca2d65b0 — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/ab2dca2d65b079768230a7c3d825afeefa330215
GitHub commit

commit 6e39f4c94def (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 6e39f4c94def — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/6e39f4c94deff7a60d382c2d95883e0ea49ff691
GitHub commit

commit 59b1744a6cb6 (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 59b1744a6cb6 — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/59b1744a6cb62746db418ac06fc5e359fd25fdb7
GitHub commit

commit 109e5a5b08ad (envoyproxy/envoy)

Fix landed in envoyproxy/envoy commit 109e5a5b08ad — awaiting tagged release

https://github.com/envoyproxy/envoy/commit/109e5a5b08ad10d99074cefd55a747a16ee64da7
GitHub advisoryMentions a patch (unverified)

Incomplete fix for CVE-2026-26310: copyInternetAddressAndPort crashes on scoped IPv6 addresses in ORIGINAL_DST clusters · Advisory · envoyproxy/envoy · GitHub

https://github.com/envoyproxy/envoy/security/advisories/GHSA-jp5f-qr64-c9vw

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 / 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.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  4. 2026-10-30 06:55 UTCOSV refresh
  5. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  8. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  9. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  10. 2026-10-25 14:05 UTCEG score recompute
  11. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  12. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  13. 2026-10-22 19:02 UTCEG score recompute
  14. 2026-10-22 19:02 UTCVendor advisory
  15. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  17. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  18. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  20. 2026-10-18 03:15 UTCEG score recompute
  21. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  22. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  23. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  24. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  25. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
Show 68 more
  1. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-10-12 15:40 UTCEG score recompute
  3. 2026-10-11 19:26 UTCEG score recompute
  4. 2026-10-11 16:42 UTCEG score recompute
  5. 2026-10-11 14:01 UTCEG score recompute
  6. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  7. 2026-10-11 06:48 UTCEG score recompute
  8. 2026-10-11 06:48 UTCVendor advisory
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  10. 2026-10-10 08:09 UTCEG score recompute
  11. 2026-10-10 08:09 UTCVendor advisory
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-10-09 09:28 UTCEG score recompute
  14. 2026-10-09 09:28 UTCVendor advisory
  15. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-10-08 10:48 UTCEG score recompute
  17. 2026-10-08 10:48 UTCVendor advisory
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  19. 2026-10-07 11:46 UTCEG score recompute
  20. 2026-10-07 11:46 UTCVendor advisory
  21. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  22. 2026-10-06 13:03 UTCEG score recompute
  23. 2026-10-06 13:03 UTCVendor advisory
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-10-05 14:23 UTCVendor advisory
  26. 2026-10-05 03:21 UTCEG score recompute
  27. 2026-10-05 03:21 UTCVendor advisory
  28. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  29. 2026-10-04 04:41 UTCEG score recompute
  30. 2026-10-04 04:41 UTCVendor advisory
  31. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  32. 2026-10-03 06:02 UTCEG score recompute
  33. 2026-10-03 06:02 UTCVendor advisory
  34. 2026-10-02 07:22 UTCEG score recompute
  35. 2026-10-02 07:22 UTCVendor advisory
  36. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  37. 2026-10-01 08:42 UTCEG score recompute
  38. 2026-10-01 08:42 UTCVendor advisory
  39. 2026-09-30 10:02 UTCEG score recompute
  40. 2026-09-30 10:02 UTCVendor advisory
  41. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  42. 2026-09-29 11:23 UTCEG score recompute
  43. 2026-09-29 11:23 UTCVendor advisory
  44. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  45. 2026-09-28 12:42 UTCVendor advisory
  46. 2026-09-27 14:02 UTCEG score recompute
  47. 2026-09-27 14:02 UTCVendor advisory
  48. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  49. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  50. 2026-09-26 15:19 UTCEG score recompute
  51. 2026-09-26 15:19 UTCVendor advisory
  52. 2026-09-25 16:39 UTCVendor advisory
  53. 2026-09-24 17:59 UTCEG score recompute
  54. 2026-09-24 17:59 UTCVendor advisory
  55. 2026-09-23 18:45 UTCEG score recompute
  56. 2026-09-23 18:45 UTCVendor advisory
  57. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  58. 2026-09-23 13:00 UTCEG score recompute
  59. 2026-09-23 13:00 UTCVendor advisory
  60. 2026-09-22 14:20 UTCEG score recompute
  61. 2026-09-22 14:20 UTCVendor advisory
  62. 2026-09-22 13:36 UTCEG score recompute
  63. 2026-09-22 13:36 UTCVendor advisory
  64. 2026-09-21 20:18 UTCEG score recompute
  65. 2026-09-21 20:18 UTCVendor advisory
  66. 2026-09-21 19:45 UTCEG score recomputeFirst assessed: 5.3 MEDIUM
  67. 2026-09-21 19:45 UTCVendor advisory
  68. 2026-09-21 19:45 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-73549?
CVE-2026-73549 is a medium-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's Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string…
When was the CVE record for CVE-2026-73549 published?
The CVE record for CVE-2026-73549 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-2026-73549 actively exploited?
CVE-2026-73549 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73549?
CVE-2026-73549 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73549?
A fix for CVE-2026-73549 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-73549 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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