CVE-2026-61909

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0

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

An issue was discovered in Cyrus IMAP before 3.12.4. CalDAV/CardDAV multiget bypasses a per-href ACL. An authenticated DAV user with some shared access to another user's calendar or address book could read even unshared events or contacts by including the target hrefs in a calendar-multiget or addressbook-multiget REPORT.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
19(Track)
EG Risk 19/100SSVC: 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
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

September 9, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

Cyrus IMAP 3.8.8 Release Notes — Cyrus IMAP 3.12.4 documentation

https://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html
generic

Cyrus IMAP 3.12.4 Release Notes — Cyrus IMAP 3.12.4 documentation

https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html
generic

Cyrus IMAP 3.10.4 Release Notes — Cyrus IMAP 3.12.4 documentation

https://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html
generic

What is Cyrus IMAP? — Cyrus IMAP 3.12.4 documentation

https://cyrusimap.org

Vendor Advisories for CVE-2026-61909(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 15× in last 7d / 20× 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. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 14:23 UTCEG score recompute
  3. 2026-09-18 14:23 UTCGHSA enrichment
  4. 2026-09-17 15:03 UTCGHSA enrichment
  5. 2026-09-16 15:43 UTCEG score recompute▲ 0.80
  6. 2026-09-16 15:43 UTCGHSA enrichment
  7. 2026-09-16 15:43 UTCNVD updateCVSS v3 → 4.3 · severity → MEDIUM
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-16 05:15 UTCEPSS rescore
  10. 2026-09-14 16:26 UTCEG score recompute
  11. 2026-09-14 16:26 UTCGHSA enrichment
  12. 2026-09-14 15:35 UTCEG score recompute
  13. 2026-09-14 15:35 UTCGHSA enrichment
  14. 2026-09-12 22:21 UTCEG score recompute
  15. 2026-09-12 22:21 UTCGHSA enrichment
  16. 2026-09-11 14:53 UTCEPSS rescore
  17. 2026-09-11 09:37 UTCEPSS rescore
  18. 2026-09-09 20:48 UTCEG score recompute
  19. 2026-09-09 19:55 UTCEG score recompute
  20. 2026-09-09 19:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-61909?
CVE-2026-61909 is a medium vulnerability published on September 9, 2026. An issue was discovered in Cyrus IMAP before 3.12.4. CalDAV/CardDAV multiget bypasses a per-href ACL. An authenticated DAV user with some shared access to another user's calendar or address book could read even unshared events or contacts by including the target hrefs in a calendar-multiget or…
When was CVE-2026-61909 disclosed?
CVE-2026-61909 was first published in the National Vulnerability Database on September 9, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-61909 actively exploited?
CVE-2026-61909 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 89.3% of all scored CVEs.
What is the CVSS score of CVE-2026-61909?
CVE-2026-61909 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-61909?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-61909, 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-2026-61909

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