CVE-2026-90990

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: 0.4% (36th 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-2026-84350 (ENISA EUVD) · GHSA-v742-5hjw-gqcp (GitHub Security Advisories)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.3Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

The CVE record's CNA (Checkmk GmbH) lists Checkmk GmbH Checkmk versions 2.5.0 up to but not including 2.5.0p14 as affected. No release containing a fix is confirmed on record.

Improper neutralization of newlines in filter values in the monitoring host and service list APIs in Checkmk <2.5.0p14 allows an authenticated user to inject additional Livestatus query headers, bypassing object visibility restrictions in count queries to infer information about hosts and services outside their contact groups and occupying web server and Livestatus workers for an attacker-controlled duration.

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.
Exploitation0.4% × 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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.4%
EPSS %ILE
36th
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
0.4% 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

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.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

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 22, 2026

Last Modified

September 22, 2026

Advisory Details (1)

Auto-updated Sep 22, 2026
No fix on record yet.
Web page

Werk #19604: Fix Livestatus injection via monitoring filter values

https://checkmk.com/werk/19604

Vendor Advisories for CVE-2026-90990(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 52× 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.

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. 1 repeat row among the latest 84 is merged into the row it repeats.

  1. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  5. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  6. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  7. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  8. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-10-25 13:51 UTCEG score recompute
  10. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-10-22 12:31 UTCEG score recompute
  14. 2026-10-22 12:31 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  17. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  19. 2026-10-18 03:00 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  23. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
Show 58 more
  1. 2026-10-12 14:46 UTCEG score recompute
  2. 2026-10-11 22:13 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  3. 2026-10-11 19:13 UTCEG score recompute
  4. 2026-10-11 16:30 UTCEG score recompute
  5. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  6. 2026-10-11 13:45 UTCEG score recompute
  7. 2026-10-10 21:54 UTCEG score recompute
  8. 2026-10-10 21:54 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  10. 2026-10-09 20:41 UTCEG score recompute
  11. 2026-10-09 20:41 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  12. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  13. 2026-10-08 20:24 UTCEG score recompute
  14. 2026-10-08 20:24 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  15. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  16. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  17. 2026-10-07 20:00 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  18. 2026-10-06 19:42 UTCEG score recompute
  19. 2026-10-06 19:41 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  20. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-10-05 19:23 UTCEG score recompute
  22. 2026-10-05 19:23 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  23. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-10-04 19:06 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  26. 2026-10-03 18:48 UTCEG score recompute
  27. 2026-10-03 18:48 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  28. 2026-10-02 17:47 UTCEG score recompute
  29. 2026-10-02 17:47 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  30. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  31. 2026-10-01 17:28 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  32. 2026-09-30 17:09 UTCEG score recompute
  33. 2026-09-30 17:09 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  34. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  35. 2026-09-29 16:48 UTCEG score recompute
  36. 2026-09-29 16:48 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  37. 2026-09-28 16:15 UTCEG score recompute
  38. 2026-09-28 16:15 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  39. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  40. 2026-09-27 15:57 UTCEG score recompute
  41. 2026-09-27 15:57 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  42. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  43. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  44. 2026-09-26 15:39 UTCEG score recompute
  45. 2026-09-26 15:39 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  46. 2026-09-25 15:22 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  47. 2026-09-24 15:03 UTCEG score recompute
  48. 2026-09-24 15:03 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  49. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  50. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  51. 2026-09-23 14:37 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  52. 2026-09-22 14:20 UTCEG score recompute
  53. 2026-09-22 14:19 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  54. 2026-09-22 13:27 UTCEG score recompute
  55. 2026-09-22 13:27 UTCGHSA enrichmentGHSA-v742-5hjw-gqcp
  56. 2026-09-22 11:35 UTCEG score recompute
  57. 2026-09-22 10:46 UTCEG score recomputeFirst assessed: 5.3 MEDIUM
  58. 2026-09-22 10:45 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-90990?
CVE-2026-90990 is a medium-severity vulnerability; its CVE record was published on September 22, 2026. Improper neutralization of newlines in filter values in the monitoring host and service list APIs in Checkmk <2.5.0p14 allows an authenticated user to inject additional Livestatus query headers, bypassing object visibility restrictions in count queries to infer information about hosts and services…
When was the CVE record for CVE-2026-90990 published?
The CVE record for CVE-2026-90990 was published on September 22, 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 22, 2026; the record at its source may have been updated since.
Is CVE-2026-90990 actively exploited?
CVE-2026-90990 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-90990?
CVE-2026-90990 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-2026-90990?
No fix for CVE-2026-90990 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (Checkmk GmbH) lists Checkmk GmbH Checkmk versions 2.5.0 up to but not including 2.5.0p14 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-90990 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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