CVE-2026-15576

MEDIUMPre-NVD 6.96.9
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (37th 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
Trending — 3 sources updated this week
6.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.9Exploit: 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 2.5.0p10 as affected. No release containing a fix is confirmed on record.

Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request URL, resulting in limited impact on integrity and availability. Only the Cloud, Ultimate and Ultimate MT editions are affected, as other editions do not expose relay endpoints.

CVSS v3
6.9
EG Score
6.9MEDIUMmedium confidence
EG Risk
46
EG Risk 46/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity69% × 45%
The EG Score, 6.9 of 10.
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: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.5%
EPSS %ILE
37th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

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.

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

August 21, 2026

Last Modified

August 26, 2026

Advisory Details (1)

Auto-updated Aug 21, 2026
No fix on record yet.
Web page

Werk #20174: Agent receiver: reject mTLS requests without a client certificate

https://checkmk.com/werk/20174

Vendor Advisories for CVE-2026-15576(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 16× in last 7d / 70× 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 135 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 35 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  2. 2026-10-12 16:31 UTCEG score recompute
  3. 2026-10-11 20:10 UTCEG score recompute
  4. 2026-10-11 17:22 UTCEG score recompute
  5. 2026-10-11 14:55 UTCEG score recompute
  6. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  7. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  8. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  9. 2026-10-09 06:00 UTCEG score recompute
  10. 2026-10-09 06:00 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  11. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  12. 2026-10-08 04:58 UTCEG score recompute
  13. 2026-10-08 04:57 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  14. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  15. 2026-10-06 16:58 UTCEG score recompute
  16. 2026-10-06 16:58 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  17. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  18. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  19. 2026-10-05 17:07 UTCEG score recompute
  20. 2026-10-05 17:07 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  21. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  22. 2026-10-04 16:35 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  23. 2026-10-03 16:43 UTCEG score recompute
  24. 2026-10-03 16:43 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  25. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 37th percentile
Show 75 more
  1. 2026-10-02 07:59 UTCEG score recompute
  2. 2026-10-02 07:59 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  3. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  4. 2026-10-01 07:49 UTCEG score recompute
  5. 2026-10-01 07:49 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  6. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  7. 2026-09-30 07:57 UTCEG score recompute
  8. 2026-09-30 07:57 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  9. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  10. 2026-09-29 02:15 UTCEG score recompute
  11. 2026-09-29 02:15 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  12. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  13. 2026-09-28 02:23 UTCEG score recompute
  14. 2026-09-28 02:23 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  15. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  16. 2026-09-27 02:32 UTCEG score recompute
  17. 2026-09-27 02:32 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  18. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  19. 2026-09-25 00:36 UTCEG score recompute
  20. 2026-09-25 00:36 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  21. 2026-09-23 23:50 UTCEG score recompute
  22. 2026-09-23 23:50 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  23. 2026-09-22 23:58 UTCEG score recompute
  24. 2026-09-22 23:58 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  25. 2026-09-22 00:07 UTCEG score recompute
  26. 2026-09-22 00:07 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  27. 2026-09-21 00:15 UTCEG score recompute
  28. 2026-09-21 00:15 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  29. 2026-09-20 00:23 UTCEG score recompute
  30. 2026-09-20 00:23 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  31. 2026-09-19 00:31 UTCEG score recompute
  32. 2026-09-19 00:31 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  33. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  34. 2026-09-18 00:37 UTCEG score recompute
  35. 2026-09-18 00:37 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  36. 2026-09-17 00:46 UTCEG score recompute
  37. 2026-09-17 00:46 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  38. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  39. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-09-16 00:54 UTCEG score recompute
  41. 2026-09-16 00:54 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  42. 2026-09-15 01:02 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  43. 2026-09-14 01:10 UTCEG score recompute
  44. 2026-09-14 01:10 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  45. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  46. 2026-09-13 01:19 UTCEG score recompute
  47. 2026-09-13 01:19 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  48. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  49. 2026-09-12 01:27 UTCEG score recompute
  50. 2026-09-12 01:27 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  51. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  52. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  53. 2026-09-11 01:35 UTCEG score recompute
  54. 2026-09-11 01:35 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  55. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  56. 2026-09-10 01:44 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  57. 2026-09-09 01:48 UTCEG score recompute
  58. 2026-09-09 01:48 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  59. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  60. 2026-09-07 20:43 UTCEG score recompute
  61. 2026-09-07 20:43 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  62. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  63. 2026-09-06 20:51 UTCEG score recompute
  64. 2026-09-06 20:51 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  65. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  66. 2026-09-05 20:59 UTCEG score recompute
  67. 2026-09-05 20:59 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  68. 2026-09-04 21:07 UTCEG score recompute
  69. 2026-09-04 21:07 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  70. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  71. 2026-09-03 21:02 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  72. 2026-09-02 21:07 UTCEG score recompute
  73. 2026-09-02 21:07 UTCGHSA enrichmentGHSA-8fww-64wc-46pf
  74. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  75. 2026-09-01 18:54 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-15576?
CVE-2026-15576 is a medium-severity vulnerability; its CVE record was published on August 21, 2026. Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request URL, resulting in limited impact on integrity and…
When was the CVE record for CVE-2026-15576 published?
The CVE record for CVE-2026-15576 was published on August 21, 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 August 26, 2026; the record at its source may have been updated since.
Is CVE-2026-15576 actively exploited?
CVE-2026-15576 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (37th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-15576?
CVE-2026-15576 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-15576?
No fix for CVE-2026-15576 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 2.5.0p10 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-15576 are linked in the Vendor Advisories panel on this page.

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