CVE-2026-39042

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-14. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

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

An issue in MikroTIk (SIA Mikrotikls, Latvia) RouterOS 7.21.x before v.7.21.4 and 7.22.x before v.7.22.2 allows a remote attacker to cause a denial of service via the unflatten() function in libumsg.so.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

July 13, 2026

Last Modified

July 15, 2026

Advisory Details (2)

Auto-updated Jul 15, 2026
No patch confirmed yet.
generic

Patrik Žák — Ethical Hacker & Red Teamer

https://zakpatrik.cz/blog/finding-an-integer-overflow-in-mikrotik-routeros-core-ipc-library
generic

MikroTik · Security

https://mikrotik.com/supportsec

Vendor Advisories for CVE-2026-39042(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 21× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-07-29 00:47 UTCEG score recompute
  2. 2026-07-29 00:47 UTCGHSA enrichment
  3. 2026-07-28 12:38 UTCGHSA enrichment
  4. 2026-07-28 00:29 UTCEG score recompute
  5. 2026-07-28 00:29 UTCGHSA enrichment
  6. 2026-07-27 14:13 UTCEPSS rescore
  7. 2026-07-27 12:16 UTCGHSA enrichment
  8. 2026-07-27 00:08 UTCEG score recompute
  9. 2026-07-27 00:08 UTCGHSA enrichment
  10. 2026-07-26 14:54 UTCEPSS rescore
  11. 2026-07-26 14:54 UTCEPSS rescore
  12. 2026-07-26 12:00 UTCEG score recompute
  13. 2026-07-26 12:00 UTCGHSA enrichment
  14. 2026-07-25 14:18 UTCEPSS rescore
  15. 2026-07-25 14:18 UTCEPSS rescore
  16. 2026-07-24 14:17 UTCEPSS rescore
  17. 2026-07-24 14:17 UTCEPSS rescore
  18. 2026-07-23 14:18 UTCEPSS rescore
  19. 2026-07-23 14:18 UTCEPSS rescore
  20. 2026-07-23 03:10 UTCEG score recompute
  21. 2026-07-22 14:08 UTCEPSS rescore
  22. 2026-07-21 15:24 UTCEPSS rescore
  23. 2026-07-20 17:08 UTCEPSS rescore
  24. 2026-07-19 02:29 UTCEPSS rescore
  25. 2026-07-18 10:04 UTCEPSS rescore
Show 11 more
  1. 2026-07-17 05:20 UTCGHSA enrichment
  2. 2026-07-16 17:12 UTCEG score recompute▲ 7.50
  3. 2026-07-16 17:12 UTCGHSA enrichment
  4. 2026-07-16 17:03 UTCEPSS rescore
  5. 2026-07-15 16:57 UTCEPSS rescore
  6. 2026-07-15 16:57 UTCEPSS rescore
  7. 2026-07-15 02:00 UTCEPSS rescore
  8. 2026-07-14 16:40 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
  9. 2026-07-13 22:28 UTCNVD update
  10. 2026-07-13 22:03 UTCEG score recompute
  11. 2026-07-13 22:02 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-39042?
CVE-2026-39042 is a high vulnerability published on July 13, 2026. An issue in MikroTIk (SIA Mikrotikls, Latvia) RouterOS 7.21.x before v.7.21.4 and 7.22.x before v.7.22.2 allows a remote attacker to cause a denial of service via the unflatten() function in libumsg.so.
When was CVE-2026-39042 disclosed?
CVE-2026-39042 was first published in the National Vulnerability Database on July 13, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39042 actively exploited?
CVE-2026-39042 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.4% of all scored CVEs.
What is the CVSS score of CVE-2026-39042?
CVE-2026-39042 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-39042?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39042, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-39042

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