CVE-2026-11721

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 2026-07-22. 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 — 4 sources updated this week

Also known asEUVD-2026-47709 (ENISA EUVD) · GHSA-cq66-h8mj-77hh (GitHub Security Advisories)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).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes named to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set synth-from-dnssec yes; (which is the default). This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (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
0.4%
EPSS %ILE
33rd
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
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-02). 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 none (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

July 22, 2026

Last Modified

November 2, 2026

Advisory Details (3)

Auto-updated Jul 22, 2026
Patch available.
Web page

CVE-2026-11721: Cache poisoning possible with label count discrepancy, RRSIG, and wildcards

https://kb.isc.org/docs/cve-2026-11721
Web page

Index of /isc/bind9/9.21.24

https://downloads.isc.org/isc/bind9/9.21.24
Web page

Index of /isc/bind9/9.20.26

https://downloads.isc.org/isc/bind9/9.20.26

Patch Availability(15)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntudnsutils (1:9.18.39-0ubuntu0.24.04.6) @ noble2026-11-02ubuntu
ubuntulwresd (1:9.9.5.dfsg-3ubuntu0.19+esm15) @ trusty2026-11-02ubuntu
redhatbind9.16-32:9.16.23-0.7.el8_6.112026-10-12redhat
redhatbind9.16-32:9.16.23-0.14.el8_8.92026-10-08redhat
redhatopenshift/ose-rhel-coreos-9:4.22.9.8.202609081748-02026-09-15redhat
redhatbind-32:9.11.4-26.P2.el7_9.212026-08-26redhat
redhatopenshift/ose-rhel-coreos-9:4.22.9.8.202608191915-02026-08-25redhat
redhatbind-32:9.16.23-18.el9_4.122026-08-19redhat
redhatbind-32:9.18.33-15.el10_2.102026-08-17redhat
redhatbind9.18-32:9.18.29-14.el9_8.82026-08-17redhat
redhatbind-32:9.16.23-31.el9_6.42026-08-17redhat
redhatbind-32:9.16.23-40.el9_8.82026-08-13redhat
redhatbind-32:9.11.36-16.el8_10.142026-08-13redhat
redhatbind9.16-32:9.16.23-0.22.el8_10.122026-08-13redhat
redhatbind-main-9.20.26-0.1.hum12026-08-12redhat

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:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • every version up to 9.20.26-r0: fixed in 9.20.26-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • every version up to 9.20.26-r0: fixed in 9.20.26-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
bind—
  • every version up to 9.20.26-r0: fixed in 9.20.26-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.16.15-1 ... 1:9.16.50-1~deb11u5 (17 versions)
  • every version up to 1:9.16.50-1~deb11u6: fixed in 1:9.16.50-1~deb11u6
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.18.12-1 ... 1:9.18.49-1~deb12u1 (16 versions)
  • every version up to 1:9.18.49-1~deb12u2: fixed in 1:9.18.49-1~deb12u2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.20.11-4 ... 1:9.20.26-1~deb13u1~bpo12+1 (21 versions)
  • every version up to 1:9.20.26-1~deb13u1: fixed in 1:9.20.26-1~deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
bind91:9.20.11-4 ... 1:9.20.26-1~deb13u1~bpo12+1 (22 versions)
  • every version up to 1:9.20.26-1: fixed in 1:9.20.26-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 13× in last 7d / 51× 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 342 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 242 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 17:48 UTCEG score recompute
  2. 2026-11-02 17:48 UTCVendor advisory
  3. 2026-11-02 17:48 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  4. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  5. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  6. 2026-11-01 04:24 UTCEG score recompute
  7. 2026-11-01 04:24 UTCVendor advisory
  8. 2026-11-01 04:24 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  9. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  10. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  11. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  12. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  13. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  14. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  15. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  16. 2026-10-25 14:50 UTCEG score recompute
  17. 2026-10-24 18:27 UTCEG score recompute
  18. 2026-10-24 18:27 UTCVendor advisory
  19. 2026-10-24 18:27 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  22. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  23. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  24. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  25. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
Show 75 more
  1. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  2. 2026-10-18 05:04 UTCEG score recompute
  3. 2026-10-17 19:01 UTCEG score recompute
  4. 2026-10-17 19:01 UTCVendor advisory
  5. 2026-10-17 19:01 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  6. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  8. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  9. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  10. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  11. 2026-10-12 16:37 UTCEG score recompute
  12. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  13. 2026-10-11 20:13 UTCEG score recompute
  14. 2026-10-11 18:25 UTCEG score recompute
  15. 2026-10-11 14:58 UTCEG score recompute
  16. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  17. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  18. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  19. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  20. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  21. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  22. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  23. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  24. 2026-10-04 13:25 UTCEG score recompute
  25. 2026-10-04 13:25 UTCVendor advisory
  26. 2026-10-04 13:25 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  27. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  28. 2026-10-03 03:34 UTCEG score recompute
  29. 2026-10-03 03:34 UTCVendor advisory
  30. 2026-10-03 03:34 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  31. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  32. 2026-10-01 06:28 UTCEG score recompute
  33. 2026-10-01 06:28 UTCVendor advisory
  34. 2026-10-01 06:28 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  35. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  36. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  37. 2026-09-28 05:18 UTCEG score recompute
  38. 2026-09-28 05:18 UTCVendor advisory
  39. 2026-09-28 05:18 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  40. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  41. 2026-09-24 09:49 UTCVendor advisory
  42. 2026-09-24 09:49 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  43. 2026-09-23 22:26 UTCEG score recompute
  44. 2026-09-23 22:26 UTCVendor advisory
  45. 2026-09-23 22:26 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  47. 2026-09-23 10:57 UTCVendor advisory
  48. 2026-09-23 10:57 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  49. 2026-09-22 23:09 UTCEG score recompute
  50. 2026-09-22 23:09 UTCVendor advisory
  51. 2026-09-22 23:09 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  52. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  53. 2026-09-20 02:01 UTCEG score recompute
  54. 2026-09-20 02:01 UTCVendor advisory
  55. 2026-09-20 02:01 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  56. 2026-09-18 22:41 UTCEG score recompute
  57. 2026-09-18 22:41 UTCVendor advisory
  58. 2026-09-18 22:41 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  60. 2026-09-18 03:11 UTCEG score recompute
  61. 2026-09-18 03:11 UTCVendor advisory
  62. 2026-09-18 03:11 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  63. 2026-09-17 02:10 UTCEG score recompute
  64. 2026-09-17 02:10 UTCVendor advisory
  65. 2026-09-17 02:10 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-09-16 07:02 UTCEG score recompute
  67. 2026-09-16 07:02 UTCVendor advisory
  68. 2026-09-16 07:02 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  70. 2026-09-14 10:16 UTCVendor advisory
  71. 2026-09-14 10:16 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-09-13 22:26 UTCEG score recompute
  73. 2026-09-13 22:26 UTCVendor advisory
  74. 2026-09-13 22:26 UTCGHSA enrichmentGHSA-cq66-h8mj-77hh · GitHub severity HIGH · GitHub CVSS 7.5
  75. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.4% · 33rd percentile

Frequently asked(5)

What is CVE-2026-11721?
CVE-2026-11721 is a high-severity vulnerability; its CVE record was published on July 22, 2026. It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes named to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For…
When was CVE-2026-11721 made public?
CVE-2026-11721 was made public on July 22, 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 July 22, 2026. EchelonGraph's copy of the record carries a last-modified date of November 2, 2026; the record at its source may have been updated since.
Is CVE-2026-11721 actively exploited?
CVE-2026-11721 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-11721?
CVE-2026-11721 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-2026-11721?
A fix for CVE-2026-11721 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-11721 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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