CVE-2020-16117: In GNOME evolution-data-server before 3.35.91, a malicious server can crash the mail client with a NULL pointe

Q: How do I fix CVE-2020-16117?

evolution-data-server: upgrade to 3.35.91; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-16117 being exploited?

CVE-2020-16117 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-16117 affect?

CVE-2020-16117 affects evolution-data-server, debian linux. Severity is medium (CVSS 5.9). In GNOME evolution-data-server before 3.35.91, a malicious server can crash the mail client with a NULL pointer dereference by sending an invalid (e.g., minimal) CAPABILITY line on a connection attempt. This is related to imapx_free_capabil

Q: How urgent is CVE-2020-16117?

Priority 56/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

MEDIUM 5.9REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2020-16117 is a medium-severity flaw (CVSS 5.9) affecting evolution-data-server, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In GNOME evolution-data-server before 3.35.91, a malicious server can crash the mail client with a NULL pointer dereference by sending an invalid (e.g., minimal) CAPABILITY line on a connection attempt. This is related to imapx_free_capability and imapx_connect_to_server.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Weakness	CWE-476
Published	2020-07-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · gnome

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-07-29 18:15 UTCPublished CVE record published
2026-06-17 02:57 UTCUpdated Record last modified

gnome evolution-data-server UPGRADE

Affected: < 3.35.91

Fixed in: 3.35.91

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy evolution-data-server || rpm -q evolution-data-server || evolution-data-server --version

2. UPGRADE to 3.35.91 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade evolution-data-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade evolution-data-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-16117?

evolution-data-server: upgrade to 3.35.91; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-16117 being exploited?

CVE-2020-16117 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-16117 affect?

CVE-2020-16117 affects evolution-data-server, debian linux. Severity is medium (CVSS 5.9). In GNOME evolution-data-server before 3.35.91, a malicious server can crash the mail client with a NULL pointer dereference by sending an invalid (e.g., minimal) CAPABILITY line on a connection attempt. This is related to imapx_free_capabil

How urgent is CVE-2020-16117?

Priority 56/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2020-14928 MEDIUM 5.9 UPGRADE MITIGATE evolution-data-server (eds) through 3.36.3 has a STARTTLS buffering issue that affects SMTP and POP3
CVE-2009-0587 HIGH 7.5 UPGRADE Multiple integer overflows in Evolution Data Server (aka evolution-data-server) before 2.24.5 allow context-de
CVE-2009-0582 MEDIUM 5.8 UPGRADE The ntlm_challenge function in the NTLM SASL authentication mechanism in camel/camel-sasl-ntlm.c in Camel in E

References

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