CVE-2026-3593

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 1.5% (74th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 7.4 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-05-20) is not newer than that change (2026-09-01), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week

Also known asEUVD-2026-31108 (ENISA EUVD) · GHSA-8v2c-7qqj-7wp7 (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
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: 1.5%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
45
EG Risk 45/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.5% × 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
1.5%
EPSS %ILE
74th
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
1.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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

May 20, 2026

Last Modified

September 1, 2026

Advisory Details (7)

Auto-updated Oct 31, 2026
Patch available.
Web page

Index of /isc/bind9/9.21.22

https://downloads.isc.org/isc/bind9/9.21.22
Web page

Index of /isc/bind9/9.20.23

https://downloads.isc.org/isc/bind9/9.20.23
Web page

CVE-2026-3593: Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation

https://kb.isc.org/docs/cve-2026-3593
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3593.json
Red HatMentions a patch (unverified)

2479770 – (CVE-2026-3593) CVE-2026-3593 bind: Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation

https://bugzilla.redhat.com/show_bug.cgi?id=2479770
Red HatMentions a patch (unverified)

CVE-2026-3593 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-3593
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:7412

Vendor Advisories for CVE-2026-3593(3)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntubind9-utils (1:9.20.18-1ubuntu2.1) @ resolute2026-11-01ubuntu
redhatbind-main-9.18.48-1.1.hum12026-04-10redhat

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.

Affected Packages

(7 across 7 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • 9.20.0 up to 9.18.49-r0: fixed in 9.18.49-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • 9.20.0 up to 9.18.49-r0: fixed in 9.18.49-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • 9.20.0 up to 9.20.23-r0: fixed in 9.20.23-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • 9.20.0 up to 9.20.23-r0: fixed in 9.20.23-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • 9.20.0 up to 9.20.23-r0: fixed in 9.20.23-r0
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.20.11-4 ... 1:9.20.23-1~deb13u1~bpo12+1 (17 versions)
  • every version up to 1:9.20.23-1~deb13u1: fixed in 1:9.20.23-1~deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.20.11-4 ... 1:9.20.23-1~deb13u1~bpo12+1 (18 versions)
  • every version up to 1:9.20.23-1: fixed in 1:9.20.23-1
—

Weakness Classification(2)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 28× in last 7d / 99× 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 490 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 390 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 09:30 UTCEG score recompute
  2. 2026-11-02 09:30 UTCVendor advisory
  3. 2026-11-02 09:30 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  4. 2026-11-01 16:34 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  5. 2026-11-01 08:53 UTCEG score recompute
  6. 2026-11-01 08:53 UTCVendor advisory
  7. 2026-11-01 08:53 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  8. 2026-10-31 16:32 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  9. 2026-10-31 08:15 UTCEG score recompute
  10. 2026-10-31 08:15 UTCVendor advisory
  11. 2026-10-31 08:15 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  12. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  13. 2026-10-30 07:38 UTCEG score recompute
  14. 2026-10-30 07:38 UTCVendor advisory
  15. 2026-10-30 07:38 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  16. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  17. 2026-10-29 07:01 UTCEG score recompute
  18. 2026-10-29 07:01 UTCVendor advisory
  19. 2026-10-29 07:01 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  20. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  21. 2026-10-28 06:24 UTCEG score recompute
  22. 2026-10-28 06:24 UTCVendor advisory
  23. 2026-10-28 06:24 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  24. 2026-10-27 16:31 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  25. 2026-10-27 05:46 UTCEG score recompute
Show 75 more
  1. 2026-10-27 05:46 UTCVendor advisory
  2. 2026-10-27 05:46 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  3. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  4. 2026-10-26 01:07 UTCEG score recompute
  5. 2026-10-26 01:07 UTCVendor advisory
  6. 2026-10-26 01:07 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 1.5% · 74th percentile
  8. 2026-10-25 14:32 UTCEG score recompute
  9. 2026-10-25 00:28 UTCEG score recompute
  10. 2026-10-25 00:28 UTCVendor advisory
  11. 2026-10-25 00:28 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  12. 2026-10-24 16:32 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  13. 2026-10-23 23:51 UTCEG score recompute
  14. 2026-10-23 23:51 UTCVendor advisory
  15. 2026-10-23 23:50 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  16. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  17. 2026-10-22 23:10 UTCEG score recompute
  18. 2026-10-22 23:10 UTCVendor advisory
  19. 2026-10-22 23:10 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  20. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  21. 2026-10-21 22:33 UTCEG score recompute
  22. 2026-10-21 22:33 UTCVendor advisory
  23. 2026-10-21 22:33 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  24. 2026-10-21 16:33 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  25. 2026-10-20 21:56 UTCEG score recompute
  26. 2026-10-20 21:56 UTCVendor advisory
  27. 2026-10-20 21:56 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  28. 2026-10-20 16:33 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  29. 2026-10-19 21:19 UTCEG score recompute
  30. 2026-10-19 21:19 UTCVendor advisory
  31. 2026-10-19 21:18 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  32. 2026-10-19 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  33. 2026-10-18 20:22 UTCEG score recompute
  34. 2026-10-18 20:22 UTCVendor advisory
  35. 2026-10-18 20:22 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  36. 2026-10-18 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  37. 2026-10-18 03:44 UTCEG score recompute
  38. 2026-10-17 19:44 UTCEG score recompute
  39. 2026-10-17 19:44 UTCVendor advisory
  40. 2026-10-17 19:44 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  41. 2026-10-17 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  42. 2026-10-16 19:06 UTCEG score recompute
  43. 2026-10-16 19:06 UTCVendor advisory
  44. 2026-10-16 19:05 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  45. 2026-10-16 16:42 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  46. 2026-10-15 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  47. 2026-10-15 16:18 UTCEG score recompute
  48. 2026-10-15 16:18 UTCVendor advisory
  49. 2026-10-15 16:17 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  50. 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  51. 2026-10-14 10:22 UTCEG score recompute
  52. 2026-10-14 10:22 UTCVendor advisory
  53. 2026-10-14 10:21 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  54. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  55. 2026-10-13 08:53 UTCEG score recompute
  56. 2026-10-13 08:53 UTCVendor advisory
  57. 2026-10-13 08:53 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  58. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  59. 2026-10-12 16:11 UTCEG score recompute
  60. 2026-10-12 08:15 UTCVendor advisory
  61. 2026-10-12 08:15 UTCGHSA enrichmentGHSA-8v2c-7qqj-7wp7 · GitHub severity HIGH · GitHub CVSS 7.4
  62. 2026-10-11 19:53 UTCEG score recompute
  63. 2026-10-11 17:06 UTCEG score recompute
  64. 2026-10-11 14:33 UTCEG score recompute
  65. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  66. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  67. 2026-10-10 00:55 UTCOSV refresh
  68. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  69. 2026-10-08 17:12 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  70. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  71. 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  72. 2026-10-05 17:43 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  73. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  74. 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  75. 2026-10-01 19:50 UTCEPSS rescoreEPSS 1.1% · 64th percentile

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Frequently asked(5)

What is CVE-2026-3593?
CVE-2026-3593 is a critical-severity vulnerability; its CVE record was published on May 20, 2026. A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.
When was CVE-2026-3593 made public?
CVE-2026-3593 was made public on May 20, 2026: that is the date its CVE record's CNA, Internet Systems Consortium (ISC), gives for when the vulnerability was made public. The CVE record itself was published on May 20, 2026. EchelonGraph's copy of the record carries a last-modified date of September 1, 2026; the record at its source may have been updated since.
Is CVE-2026-3593 actively exploited?
CVE-2026-3593 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.5% probability of exploitation in the next 30 days (74th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-3593?
CVE-2026-3593 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-3593?
A fix for CVE-2026-3593 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-3593 are linked in the Vendor Advisories panel on this page.

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