CVE-2026-123586

HIGHPre-NVD 7.57.5
EchelonGraph scoreHIGH confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-11-08. 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

Also known asEUVD-2026-119345 (ENISA EUVD) · GHSA-fcx4-92qj-2p7q (GitHub Security Advisories) · RUSTSEC-2026-0516 (OSV.dev) · RUSTSEC-2026-0522 (OSV.dev)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: 0.3%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.

CVSS v3
7.5
EG Score
7.5HIGHhigh 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.
Exploitation0.3% × 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
0.3%
EPSS %ILE
28th
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
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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

November 8, 2026

Last Modified

November 10, 2026

Advisory Details (2)

Auto-updated Nov 8, 2026
Patch available. Sources: github.
Web page

Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals | Advisories | VulnCheck

https://www.vulncheck.com/advisories/hickory-dns-0.25.0-alpha.3-through-0.25.2-query-amplification-via-cyclic-referrals
GitHub advisoryMentions a patch (unverified)

Cyclic sibling domain name server referrals without glue records cause exponential upstream query amplification in the recursor · Advisory · hickory-dns/hickory-dns · GitHub

https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-cx5j-p54p-q756

Vendor Advisories for CVE-2026-123586(1)

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

Affected Packages

(4 across 2 ecosystems)
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
rust-hickory-recursor0.24.1-1 ... 0.25.2-6 (7 versions)
  • every version on: no fix on record
—
rust-hickory-resolver0.24.4-1 ... 0.26.3-1 (9 versions)
  • every version on: no fix on record
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
rust-hickory-recursor0.24.1-1 ... 0.25.2-6 (7 versions)
  • every version on: no fix on record
—
rust-hickory-resolver0.24.4-1 ... 0.26.1-1 (8 versions)
  • every version up to 0.26.3-1: fixed in 0.26.3-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 13× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  3. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  4. 2026-11-11 03:49 UTCGHSA enrichmentGHSA-fcx4-92qj-2p7q · GitHub severity HIGH · GitHub CVSS 7.5
  5. 2026-11-10 22:30 UTCEchelonGraph re-scored
  6. 2026-11-10 22:30 UTCGHSA enrichmentGHSA-fcx4-92qj-2p7q · GitHub severity HIGH · GitHub CVSS 7.5
  7. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  8. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  9. 2026-11-09 14:28 UTCEchelonGraph re-scored
  10. 2026-11-09 14:28 UTCGHSA enrichmentGHSA-fcx4-92qj-2p7q · GitHub severity HIGH · GitHub CVSS 7.5
  11. 2026-11-09 14:00 UTCEchelonGraph re-scored
  12. 2026-11-09 14:00 UTCGHSA enrichmentGHSA-fcx4-92qj-2p7q · GitHub severity HIGH · GitHub CVSS 7.5
  13. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  14. 2026-11-08 03:46 UTCEchelonGraph re-scored
  15. 2026-11-08 03:46 UTCGHSA enrichmentGHSA-fcx4-92qj-2p7q · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-11-08 03:04 UTCENISA EUVD ID recordedEUVD-2026-119345 · Source: ENISA EUVD
  17. 2026-11-08 02:27 UTCEchelonGraph re-scored
  18. 2026-11-08 01:47 UTCEchelonGraph re-scoredFirst assessed: 7.5 HIGH
  19. 2026-11-08 01:46 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-123586?
CVE-2026-123586 is a high-severity vulnerability; its CVE record was published on November 8, 2026. Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the…
When was CVE-2026-123586 made public?
CVE-2026-123586 was made public on September 3, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on November 8, 2026. EchelonGraph's copy of the record carries a last-modified date of November 10, 2026; the record at its source may have been updated since.
Is CVE-2026-123586 actively exploited?
CVE-2026-123586 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (28th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-123586?
CVE-2026-123586 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-2026-123586?
A fix for CVE-2026-123586 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-123586 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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