CVE-2021-37746

textview_uri_security_check in textview.c in Claws Mail before 3.18.0, and Sylpheed through 3.7.0, does not have sufficient link checks before accepting a click.

Published: 2021-07-30 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-37746 is rated Moderate Risk (47.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.48%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-37746

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.35% 0.48% +0.14%
2 2025-11-18 0.48% 0.35% -0.14%
3 2025-09-30 — 0.48% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-37746

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-37746

OS Trackers for CVE-2021-37746

vendor priority summary link
alpine medium CVE-2021-37746: 1 source package rows (claws-mail); 4 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 4. https://security.alpinelinux.org/vuln/CVE-2021-37746
debian not yet assigned CVE-2021-37746 not yet assigned priority: Debian including 2 source packages (claws-mail, sylpheed), 8 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5, open 3. https://security-tracker.debian.org/tracker/CVE-2021-37746
ubuntu medium CVE-2021-37746 medium priority: Ubuntu including 2 source packages (claws-mail, sylpheed), 30 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 20, needs-triage 8, DNE 2. https://ubuntu.com/security/CVE-2021-37746

Affected software / configurations for CVE-2021-37746

Vendor Product Version Raw CPE
claws-mail claws-mail < 3.18.0 cpe:2.3:a:claws-mail:claws-mail:*:*:*:*:*:*:*:*
sylpheed_project sylpheed <= 3.7.0 cpe:2.3:a:sylpheed_project:sylpheed:*:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

References for CVE-2021-37746

cvelogic Threat Intelligence