CVE-2026-103010

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-10-08. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.8Exploit: None knownExposed services: Not assessed

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

Heap-based buffer overflow in the legacy Blowfish decryption routine (BlowFishEncryptor::DecryptFromString) in Progressive Robot hMailServer 6.0.0 through 6.3.3 on Windows allows a local interactive user with no hMailServer credentials to write bytes of their choosing past the end of a 255-byte heap buffer in the hMailServer service process, which runs as LocalSystem by default. The user does this by passing a long hexadecimal string to the COM method Utilities.BlowfishDecrypt, which checked no authentication. The routine converted hexadecimal input of any length into a fixed 255-byte buffer before decrypting it in place. The result is a denial of service (service crash), and possibly code execution with the privileges of the service account.

CVSS v3
7.8
EG Score
7.8HIGHhigh confidence
EG Risk
35
EG Risk 35/100CISA SSVC

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
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.2%
EPSS %ILE
4th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* 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, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 8, 2026

Last Modified

October 8, 2026

Advisory Details (3)

Auto-updated Oct 8, 2026
No fix on record yet.
generic

Heap overflow in the legacy Blowfish encryptor (all releases to 6.3.5) (#49) · Issues · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/work_items/49
generic

hMailServer 6.3.4 · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.4
generic

Attachments opened somewhere safe, the roadmap row: a message from outside... (135a1908) · Commits · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/commit/135a1908ff820ed587d5f180f98c53bd010d8931

Vendor Advisories for CVE-2026-103010(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 / 16× 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. 2026-10-11 01:09 UTCEG score recompute
  2. 2026-10-11 01:09 UTCGHSA enrichment
  3. 2026-10-10 19:59 UTCEPSS rescore
  4. 2026-10-10 12:09 UTCGHSA enrichment
  5. 2026-10-09 23:12 UTCEG score recompute
  6. 2026-10-09 23:12 UTCGHSA enrichment
  7. 2026-10-09 20:06 UTCEPSS rescore
  8. 2026-10-09 10:15 UTCGHSA enrichment
  9. 2026-10-08 21:19 UTCGHSA enrichment
  10. 2026-10-08 15:23 UTCEG score recompute
  11. 2026-10-08 15:23 UTCGHSA enrichment
  12. 2026-10-08 14:53 UTCEG score recompute
  13. 2026-10-08 14:52 UTCGHSA enrichment
  14. 2026-10-08 11:24 UTCEG score recompute
  15. 2026-10-08 10:57 UTCEG score recompute
  16. 2026-10-08 10:56 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-103010?
CVE-2026-103010 is a high vulnerability published on October 8, 2026. Heap-based buffer overflow in the legacy Blowfish decryption routine (BlowFishEncryptor::DecryptFromString) in Progressive Robot hMailServer 6.0.0 through 6.3.3 on Windows allows a local interactive user with no hMailServer credentials to write bytes of their choosing past the end of a 255-byte…
When was CVE-2026-103010 disclosed?
CVE-2026-103010 was first published on October 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-103010 actively exploited?
CVE-2026-103010 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (4th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-103010?
CVE-2026-103010 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-103010?
No fix for CVE-2026-103010 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 vendor advisories EchelonGraph has for CVE-2026-103010 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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