DEBIAN-CVE-2026-40203

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Source
https://security-tracker.debian.org/tracker/CVE-2026-40203
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40203.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-40203
Upstream
  • CVE-2026-40203
Published
2026-08-28T12:16:28Z
Modified
2026-09-14T17:03:10Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
Summary
[none]
Details

When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.

References

Affected packages

Debian:12 / dovecot

Package

Name
dovecot
Purl
pkg:deb/debian/dovecot?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1:2.*
1:2.3.19.1+dfsg1-2.1
1:2.3.19.1+dfsg1-2.1+deb12u1
1:2.3.19.1+dfsg1-2.1+deb12u2
1:2.3.19.1+dfsg1-2.1+deb12u3
1:2.3.19.1+dfsg1-2.1+deb12u4
1:2.3.19.1+dfsg1-2.1+deb12u5
1:2.3.19.1+dfsg1-2.1+deb12u6
1:2.3.20+dfsg1-1
1:2.3.21+dfsg1-1
1:2.3.21+dfsg1-2
1:2.3.21+dfsg1-3~bpo12+1
1:2.3.21+dfsg1-3
1:2.3.21.1+dfsg1-1~bpo12+1
1:2.3.21.1+dfsg1-1
1:2.4.0+dfsg1-1~exp1
1:2.4.0+dfsg1-1~exp2
1:2.4.0+dfsg1-1~exp3
1:2.4.0+dfsg1-1~exp4
1:2.4.0+dfsg1-1~exp5
1:2.4.0+dfsg1-1~exp6
1:2.4.1+dfsg1-1~exp1
1:2.4.1+dfsg1-1~exp2
1:2.4.1+dfsg1-1
1:2.4.1+dfsg1-2
1:2.4.1+dfsg1-3
1:2.4.1+dfsg1-4
1:2.4.1+dfsg1-5
1:2.4.1+dfsg1-6~exp1
1:2.4.1+dfsg1-6
1:2.4.1+dfsg1-7
1:2.4.1+dfsg1-8
1:2.4.1+dfsg1-9
1:2.4.2+dfsg1-1
1:2.4.2+dfsg1-2
1:2.4.2+dfsg1-3
1:2.4.2+dfsg1-4
1:2.4.3+dfsg1-1
1:2.4.3+dfsg1-2
1:2.4.4+dfsg1-1
1:2.4.4+dfsg1-2
1:2.4.5+dfsg1-1
1:2.4.5+dfsg1-2

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40203.json"

Debian:13 / dovecot

Package

Name
dovecot
Purl
pkg:deb/debian/dovecot?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1:2.*
1:2.4.1+dfsg1-6
1:2.4.1+dfsg1-6+deb13u1
1:2.4.1+dfsg1-6+deb13u2
1:2.4.1+dfsg1-6+deb13u3
1:2.4.1+dfsg1-6+deb13u4
1:2.4.1+dfsg1-6+deb13u5
1:2.4.1+dfsg1-6+deb13u6
1:2.4.1+dfsg1-7
1:2.4.1+dfsg1-8
1:2.4.1+dfsg1-9
1:2.4.2+dfsg1-1
1:2.4.2+dfsg1-2
1:2.4.2+dfsg1-3
1:2.4.2+dfsg1-4
1:2.4.3+dfsg1-1
1:2.4.3+dfsg1-2
1:2.4.4+dfsg1-1
1:2.4.4+dfsg1-2
1:2.4.5+dfsg1-1
1:2.4.5+dfsg1-2

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40203.json"

Debian:14 / dovecot

Package

Name
dovecot
Purl
pkg:deb/debian/dovecot?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1:2.4.5+dfsg1-1

Affected versions

1:2.*
1:2.4.1+dfsg1-6
1:2.4.1+dfsg1-7
1:2.4.1+dfsg1-8
1:2.4.1+dfsg1-9
1:2.4.2+dfsg1-1
1:2.4.2+dfsg1-2
1:2.4.2+dfsg1-3
1:2.4.2+dfsg1-4
1:2.4.3+dfsg1-1
1:2.4.3+dfsg1-2
1:2.4.4+dfsg1-1
1:2.4.4+dfsg1-2

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40203.json"