CVE-2026-61551

HIGHPre-NVD 8.68.6
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9% (60th 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-2026-83209 (ENISA EUVD)Source: ENISA EUVD

8.6EG
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: 0.9%CVSS: 8.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Icinga 2 is an open source monitoring system. Prior to 2.14.9, 2.15.4, and 2.16.2, parsing deeply nested JSON can exhaust the call stack because nesting depth is not bounded. The affected JSON parsing paths are reachable by unauthenticated network clients through the Icinga 2 service on TCP port 5665, allowing a remote attacker to crash the process, while possible code execution has not been demonstrated. This issue is fixed in versions 2.14.9, 2.15.4, and 2.16.2.

CVSS v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
54
EG Risk 54/100

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)
Severity86% × 45%
Impact severity (EG Severity): CVSS 8.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.9% × 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
0.9%
EPSS %ILE
60th
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 (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.

EG Severity
8.6 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
0.9% 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 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

September 18, 2026

Last Modified

September 24, 2026

Advisory Details (10)

Auto-updated Sep 18, 2026
Patch available. Sources: github_release, github, github_pr, github_commit.
Web page

Releasing Icinga 2 v2.16.2, 2.15.4 and 2.14.9

https://icinga.com/blog/icinga2-security-release-v2-16-2
GitHub release Patch Available

Icinga 2 v2.16.2

Patch available: Icinga/icinga2 v2.16.2

https://github.com/Icinga/icinga2/releases/tag/v2.16.2
GitHub release Patch Available

Icinga 2 v2.15.4

Patch available: Icinga/icinga2 v2.15.4

https://github.com/Icinga/icinga2/releases/tag/v2.15.4
GitHub release Patch Available

Icinga 2 v2.14.9

Patch available: Icinga/icinga2 v2.14.9

https://github.com/Icinga/icinga2/releases/tag/v2.14.9
GitHub commit Patch Available

commit ed163a8aa9d2 (Icinga/icinga2)

Patch available: Icinga/icinga2 v2.16.2 (contains commit ed163a8aa9d2)

https://github.com/Icinga/icinga2/commit/ed163a8aa9d296820dd2ad14c47bf3f6a3fcce7d
GitHub commit

commit 4964d2444ca5 (Icinga/icinga2)

Fix landed in Icinga/icinga2 commit 4964d2444ca5 — awaiting tagged release

https://github.com/Icinga/icinga2/commit/4964d2444ca5c4fae9036054554e1c6e0025fb89
GitHub commit Patch Available

commit 3d9166ff52ff (Icinga/icinga2)

Patch available: Icinga/icinga2 v2.15.4 (contains commit 3d9166ff52ff)

https://github.com/Icinga/icinga2/commit/3d9166ff52ff1a64a286c39af57957d63442c137
GitHub commit Patch Available

commit 391504eaa9ed (Icinga/icinga2)

Patch available: Icinga/icinga2 v2.14.9 (contains commit 391504eaa9ed)

https://github.com/Icinga/icinga2/commit/391504eaa9ed9aee81f84008c57ec821974b74ee
GitHub pull request

[GHSA-wh38-wg57-5w7g] Fix stack overflow due to deeply nested data structures

Fix merged in Icinga/icinga2 PR #10908 on 2026-06-29 — awaiting tagged release

https://github.com/Icinga/icinga2/pull/10908
GitHub advisoryMentions a patch (unverified)

Stack overflow via deeply nested JSON objects · Advisory · Icinga/icinga2 · GitHub

https://github.com/Icinga/icinga2/security/advisories/GHSA-wh38-wg57-5w7g

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
icinga22.13.6-2 ... 2.16.5-1 (32 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
icinga22.14.6-1
  • every version up to 2.14.6-1+deb13u1: fixed in 2.14.6-1+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
icinga22.14.6-1 ... 2.16.1-1~exp1 (14 versions)
  • every version up to 2.16.2-1: fixed in 2.16.2-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 47× 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 0.9% · 60th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  5. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  6. 2026-10-28 06:59 UTCEG score recompute
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  8. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  9. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  10. 2026-10-25 14:14 UTCEG score recompute
  11. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  12. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  13. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  14. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  15. 2026-10-20 19:01 UTCEG score recompute
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  17. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  18. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  19. 2026-10-18 03:25 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  21. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  22. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  23. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
  24. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  25. 2026-10-13 13:25 UTCEG score recompute
Show 49 more
  1. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  2. 2026-10-12 15:50 UTCEG score recompute
  3. 2026-10-11 19:34 UTCEG score recompute
  4. 2026-10-11 16:49 UTCEG score recompute
  5. 2026-10-11 14:11 UTCEG score recompute
  6. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  7. 2026-10-11 02:47 UTCEG score recompute
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  9. 2026-10-09 22:50 UTCEG score recompute
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  11. 2026-10-08 20:24 UTCEG score recompute
  12. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  13. 2026-10-08 07:08 UTCEG score recompute
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  15. 2026-10-07 03:51 UTCEG score recompute
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  17. 2026-10-06 01:34 UTCEG score recompute
  18. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  19. 2026-10-05 12:01 UTCEG score recompute
  20. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  21. 2026-10-03 20:35 UTCEG score recompute
  22. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  23. 2026-10-02 18:17 UTCEG score recompute
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  25. 2026-10-02 05:00 UTCEG score recompute
  26. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  27. 2026-10-01 02:43 UTCEG score recompute
  28. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  29. 2026-09-30 00:25 UTCEG score recompute
  30. 2026-09-29 07:24 UTCEG score recompute
  31. 2026-09-28 18:16 UTCEG score recompute
  32. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  33. 2026-09-27 15:22 UTCEG score recompute
  34. 2026-09-27 02:14 UTCEG score recompute
  35. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  36. 2026-09-26 13:06 UTCEG score recompute
  37. 2026-09-24 21:24 UTCEG score recompute
  38. 2026-09-24 21:12 UTCEG score recompute
  39. 2026-09-24 19:04 UTCEG score recompute
  40. 2026-09-24 05:56 UTCEG score recompute
  41. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  42. 2026-09-23 03:40 UTCEG score recompute
  43. 2026-09-22 01:18 UTCEG score recompute
  44. 2026-09-20 23:02 UTCEG score recompute
  45. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  46. 2026-09-19 20:43 UTCEG score recompute
  47. 2026-09-18 18:27 UTCEG score recompute
  48. 2026-09-18 17:29 UTCEG score recomputeFirst assessed: 8.6 HIGH
  49. 2026-09-18 17:29 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-61551?
CVE-2026-61551 is a high-severity vulnerability; its CVE record was published on September 18, 2026. Icinga 2 is an open source monitoring system. Prior to 2.14.9, 2.15.4, and 2.16.2, parsing deeply nested JSON can exhaust the call stack because nesting depth is not bounded. The affected JSON parsing paths are reachable by unauthenticated network clients through the Icinga 2 service on TCP port…
When was the CVE record for CVE-2026-61551 published?
The CVE record for CVE-2026-61551 was published on September 18, 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 September 24, 2026; the record at its source may have been updated since.
Is CVE-2026-61551 actively exploited?
CVE-2026-61551 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (60th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-61551?
CVE-2026-61551 has a CVSS base score of 8.6 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-61551?
A fix for CVE-2026-61551 is available: update to the fixed version the vendor names in its advisory.

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