CVE-2026-107575

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-10-08. A secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
Trending — 4 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • 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.

Inefficient algorithmic complexity in the SPF macro expansion of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to consume worker-thread time by publishing a crafted SPF record. RFC 7208 section 7.1 requires a name too long to look up to lose whole labels from the left; the server did this by removing one label at a time and copying the rest of the name each time, so the work grew with the square of the expansion. An attacker who publishes an SPF record for a domain they control, with a mechanism whose domain-spec expands through macros to a name far longer than 253 characters, makes the SPF check of a message from that domain take several seconds. The expansion is bounded by SPF's own per-term and per-macro limits, so the loss of availability is partial.

CVSS v3
5.3
EG Score
5.3MEDIUMhigh confidence
EG Risk
39
EG Risk 39/100CISA 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
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend 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 at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.4%
EPSS %ILE
30th
KEV
Not listed

CISA SSVCTrack 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). 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 (2)

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

SPF macro expansion: cutting a name too long to look up took time quadratic in the expansion, which a sender's own SPF record drives (6.3.4-6.3.5, partial availability) (#74) · Issues · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/work_items/74
generic

hMailServer 6.3.6 · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6

Vendor Advisories for CVE-2026-107575(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 10× in last 7d / 10× 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. 2026-10-09 20:06 UTCEPSS rescore
  2. 2026-10-09 19:05 UTCGHSA enrichment
  3. 2026-10-08 21:18 UTCGHSA enrichment
  4. 2026-10-08 15:23 UTCEG score recompute
  5. 2026-10-08 15:23 UTCGHSA enrichment
  6. 2026-10-08 14:52 UTCEG score recompute
  7. 2026-10-08 14:51 UTCGHSA enrichment
  8. 2026-10-08 12:26 UTCEG score recompute
  9. 2026-10-08 11:57 UTCEG score recompute
  10. 2026-10-08 11:56 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-107575?
CVE-2026-107575 is a medium vulnerability published on October 8, 2026. Inefficient algorithmic complexity in the SPF macro expansion of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to consume worker-thread time by publishing a crafted SPF record. RFC 7208 section 7.1 requires a name too long to look up to lose whole labels…
When was CVE-2026-107575 disclosed?
CVE-2026-107575 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-2026-107575 actively exploited?
CVE-2026-107575 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (30th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107575?
CVE-2026-107575 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-2026-107575?
No fix for CVE-2026-107575 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-2026-107575 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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