NVD / CVE Program· CNA mitre

CVE-2020-10958: In Dovecot before 2.3.10.1, a crafted SMTP/LMTP message triggers an unauthenticated use-after-free bug in submission-login, submission, or…

MediumCVSS 5.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 6.1% (FIRST EPSS); higher than 93.5% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: dovecot (AlmaLinux:8) 1:2.3.8-4.el8; dovecot-devel (AlmaLinux:8) 1:2.3.8-4.el8; dovecot (Alpine:v3.10) 2.3.10.1-r0.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to dovecot (AlmaLinux:8) 1:2.3.8-4.el8; dovecot-devel (AlmaLinux:8) 1:2.3.8-4.el8; dovecot (Alpine:v3.10) 2.3.10.1-r0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In Dovecot before 2.3.10.1, a crafted SMTP/LMTP message triggers an unauthenticated use-after-free bug in submission-login, submission, or lmtp, and can lead to a crash under circumstances involving many newlines after a command.

Published: May 18, 2020
Updated: Jun 16, 2026
EPSS: 6.1% · 93th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 21 / 40 · 5.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 2 / 30 · 6.1%

CNA vs NVD score

NVD: 5.3
CNA · mitre: 5.3; agree

CVSS:3.0/AC:L/AV:N/A:L/C:N/I:N/PR:N/S:U/UI:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
dovecot	dovecot	cpe:2.3:a:dovecot:dovecot

Using dovecot? Add it to your stack and be the first to know about CVEs like this one. (Email server)

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

dovecot dovecotbefore 2.3.10.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	dovecot	before 1:2.3.8-4.el8	1:2.3.8-4.el8
AlmaLinux:8	dovecot-devel	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Alpine:v3.10	dovecot	before 2.3.10.1-r0	2.3.10.1-r0
Debian:10	dovecot	before 1:2.3.4.1-5+deb10u2	1:2.3.4.1-5+deb10u2
Debian:12	dovecot	before 1:2.3.10.1+dfsg1-1	1:2.3.10.1+dfsg1-1
openSUSE:Leap 15.1	dovecot23	before 2.3.10-lp151.2.9.1	2.3.10-lp151.2.9.1
openSUSE:Tumbleweed	dovecot23	before 2.3.16-1.6	2.3.16-1.6
openSUSE:Tumbleweed	dovecot24	before 2.4.0-1.1	2.4.0-1.1
Red Hat:enterprise_linux:8::appstream	dovecot	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-debuginfo	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-debugsource	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-mysql	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-mysql-debuginfo	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-pgsql	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-pgsql-debuginfo	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-pigeonhole	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::appstream	dovecot-pigeonhole-debuginfo	before 1:2.3.8-4.el8	1:2.3.8-4.el8
Red Hat:enterprise_linux:8::crb	dovecot-devel	before 1:2.3.8-4.el8	1:2.3.8-4.el8
SUSE:Linux Enterprise High Performance Computing 15-ESPOS	dovecot23	before 2.3.10-4.22.1	2.3.10-4.22.1
SUSE:Linux Enterprise Module for Server Applications 15 SP1	dovecot23	before 2.3.10-11.1	2.3.10-11.1

Same product

dovecot: all records

Other highest-scoring records for the same primary product.

CVE-2019-11500In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can fail for quoted strings.
58Plan
CVE-2020-7046lib-smtp in submission-login and lmtp in Dovecot 2.3.9 before 2.3.9.3 mishandles truncated UTF-8 data in command parameters, as…
45Plan
CVE-2016-8652The auth component in Dovecot before 2.2.27, when auth-policy is configured, allows a remote attackers to cause a denial of service (crash)…
37Monitor

Published before and after this one in the same product

← EarlierCVE-2020-7957Feb 12, 2020 · The IMAP and LMTP components in Dovecot 2.3.9 before 2.3.9.3 mishandle snippet generation when many characters must be read to compute the…
22Monitor
← EarlierCVE-2020-10957May 18, 2020 · In Dovecot before 2.3.10.1, unauthenticated sending of malformed parameters to a NOOP command causes a NULL Pointer Dereference and crash…
32Monitor
Later →CVE-2020-10967May 18, 2020 · In Dovecot before 2.3.10.1, remote unauthenticated attackers can crash the lmtp or submission process by sending mail with an empty…
23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
almalinux:dovecot	1:2.3.8-4.el8 · AlmaLinux:8	Package registry (OSV)
almalinux:dovecot-devel	1:2.3.8-4.el8 · AlmaLinux:8	Package registry (OSV)
alpine:dovecot	2.3.10.1-r0 · Alpine:v3.10	Package registry (OSV)
debian:dovecot	1:2.3.10.1+dfsg1-1 · Debian:12	Package registry (OSV)
opensuse:dovecot23	2.3.10-lp151.2.9.1 · openSUSE:Leap 15.1	Package registry (OSV)
opensuse:dovecot24	2.4.0-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
red hat:dovecot	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-debuginfo	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-debugsource	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-devel	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::crb	Package registry (OSV)
red hat:dovecot-mysql	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-mysql-debuginfo	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-pgsql	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-pgsql-debuginfo	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-pigeonhole	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:dovecot-pigeonhole-debuginfo	1:2.3.8-4.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
suse:dovecot23	2.3.10-4.22.1 · SUSE:Linux Enterprise High Performance Computing 15-ESPOS	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-20-362 · May 20, 2020(Dovecot Sunucu Güvenlik Güncellemesi)

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: low · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: Low

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

For records you follow, these changes also arrive as notifications. →

References

lists.opensuse.org/opensuse-security-announce/2020-05/msg00059.html

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records