CVE-2020-16094

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger...

7.5 HighFix available

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.78%Up 0.7 points since Apr 14, 2021

What each source reports

NVD Score used 7.5

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: CVE-2020-16094
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-674
Updated: 2026-11-02

CVE List No score

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: CVE-2020-16094
Updated: 2026-11-02

EUVDEUVD-2020-8061 No score

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: EUVD-2020-8061
Updated: 2026-11-03

GitHub AdvisoriesGHSA-8f6j-9hh3-9c9x No score

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger...

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: GHSA-8f6j-9hh3-9c9x
Weakness: CWE-674
Updated: 2026-11-02

OSVALPINE-CVE-2020-16094 7.5

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: ALPINE-CVE-2020-16094
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-03

OSV 7.5

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: CVE-2020-16094
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2020-16094 7.5

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: DEBIAN-CVE-2020-16094
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2020-16094 7.5

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Record: UBUNTU-CVE-2020-16094
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVMGASA-2020-0391 No score

Updated claw-mail packages fix a security vulnerability

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree (CVE-2020-16094).

Record: MGASA-2020-0391
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`claws-mail` Alpine:v3.12	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.13	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.14	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.15	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.16	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.17	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.18	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.19	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.20	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.21	before 3.17.7-r0	3.17.7-r0

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Affected packages
Package	Affected	Fixed
`claws-mail` Alpine:v3.22	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.23	before 3.17.7-r0	3.17.7-r0
`claws-mail` Alpine:v3.24	before 3.17.7-r0	3.17.7-r0
`claws-mail` Debian:12	before 3.17.7-1	3.17.7-1
`claws-mail` Debian:13	before 3.17.7-1	3.17.7-1
`claws-mail` Debian:14	before 3.17.7-1	3.17.7-1
`claws-mail` Mageia:7	before 3.17.7-1.mga7	3.17.7-1.mga7
`claws-mail` Ubuntu:16.04:LTS	All versions, plus listed versions 3.12.0-1ubuntu13.12.0-1ubuntu23.13.1-1.1ubuntu13.13.1-1.1ubuntu23.13.1-1.1ubuntu33.13.2-1ubuntu1	None known
`claws-mail` Ubuntu:18.04:LTS	All versions, plus listed versions 3.15.0-2build23.15.1-13.15.1-1ubuntu13.16.0-1	None known
`claws-mail` Ubuntu:20.04:LTS	All versions, plus listed versions 3.17.4-13.17.4-1build13.17.4-2build23.17.4-2ubuntu13.17.5-2	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	affected, aliases, references	OSV
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-16094 is a high vulnerability (CVSS 7.5) in Claws-mail, published July 28, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.78%, the 78th percentile. Fixed in claws-mail 3.17.7-r0.

References

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