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CVE-2020-15917

32
FAUCET Score

CVE-2020-15917 is a critical vulnerability in Claws Mail versions prior to 3.17.6, affecting common/session.c due to mishandling of suffix data after STARTTLS, leading to a protocol violation. With a CVSS score of 9.8, this network-exploitable flaw requires no user interaction and could result in complete compromise of confidentiality, integrity, and availability. Despite its high severity and FAUCET Risk Score of 82/100, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.17.6CPE matchmatch criteria
cpe:2.3:a:claws-mail:claws-mail:*:*:*:*:*:*:*:*
31CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
15.0CPE matchmatch criteria
cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
15.0CPE matchmatch criteria
cpe:2.3:a:opensuse:backports_sle:15.0:sp2:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.59%
Probability of exploitation in next 30 days
EPSS Percentile
83.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0259 is in the 74th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

lists.opensuse.org / opensuse-security-announce/2020-07/msg00090.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-08/msg00002.html
Broken LinkMailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-08/msg00060.html
Broken LinkMailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-09/msg00051.html
Broken LinkMailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-11/msg00013.html
Broken LinkMailing ListThird Party Advisory
git.claws-mail.org
git.claws-mail.org
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/6YVQB7NRBHO67Q74RS7RZCMW4ENRVBB4
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/G7UX65342HRVDQML4G4GEVEUB764EUM5
security.gentoo.org / glsa/202007-56
Third Party Advisory