CVE-2026-40015: open-xchange gmbh ox dovecot ce Out-of-bounds Read
Vulnerability summary
CVE-2026-40015 is a medium (CVSS 4.3) Out-of-bounds Read vulnerability in open-xchange gmbh ox dovecot ce. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 45.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 6 · Related 5Timeline
- 28-08-2026PublishedVulnerability first disclosed.
- 28-08-2026Last modifiedVulnerability information updated.
Description
An attacker that has valid credentials can open many connections to the imap-hibernate service and send invalid commands, which can intermittently cause an out-of-bounds read and crash the process. The crash interrupts hibernated IMAP sessions handled by the affected process, which can cause degradation of service for IMAP. Disable IMAP hibernation. Update to non-vulnerable version. No publicly available exploits are known.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · AlpineEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- OSV · UbuntuEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- OSV · DebianEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- NVDNIST4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
EPSS trend
Probability
0.55%
Chance of exploitation in the next 30 days
Percentile
45%
Versus all other CVEs
30-day change
+0.26 pp
From 0.29% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Open-xchange gmbh2 products
- ox dovecot ce≥ 2.3.0, < 2.4.5
- ox dovecot pro≥ 2.3.0, < 2.3.22.2 | ≥ 3.0.0, < 3.0.7 | ≥ 3.1.0, < 3.1.6
Alpine1 product
- dovecot< 2.4.5-r0
Debian1 product
- dovecotAll versions (No fix recorded) | < 1:2.4.1+dfsg1-6+deb13u7 | < 1:2.4.5+dfsg1-1
Ubuntu1 product
- dovecotAll versions (No fix recorded)
4 vendors · 5 products
