Vulnerability Name:

CVE-2020-35680 (CCN-193799)

Assigned:2020-12-24
Published:2020-12-24
Updated:2022-09-02
Summary:smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.
CVSS v3 Severity:7.5 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
7.5 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
7.8 High (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-476
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2020-35680

Source: XF
Type: UNKNOWN
opensmtpd-cve202035680-dos(193799)

Source: CCN
Type: src GIT Repository
smtpd's filter state machine can prematurely release resources leading to a crash.

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/openbsd/src/commit/6c3220444ed06b5796dedfd53a0f4becd903c0d1

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2021-848fd34b0b

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2021-71fbdecdf8

Source: MISC
Type: Third Party Advisory
https://poolp.org/posts/2020-12-24/december-2020-opensmtpd-6.8.0p1-released-fixed-several-bugs-proposed-several-diffs-book-is-on-github/

Source: GENTOO
Type: Third Party Advisory
GLSA-202105-12

Source: CCN
Type: OpenSMTPD Mailing List, Wed, 23 Dec 2020 12:29:44 -0800
OpenSMTPD 6.8.0p1 has just been released

Source: MISC
Type: Release Notes, Third Party Advisory
https://www.mail-archive.com/misc@opensmtpd.org/msg05188.html

Vulnerable Configuration:Configuration 1:
  • cpe:/a:opensmtpd:opensmtpd:6.8.0:-:*:*:*:*:*:*
  • OR cpe:/a:opensmtpd:opensmtpd:*:*:*:*:*:*:*:* (Version < 6.8.0)
  • OR cpe:/a:opensmtpd:opensmtpd:6.8.0:patch1-rc1:*:*:*:*:*:*

    • Configuration 2:
  • cpe:/o:fedoraproject:fedora:32:*:*:*:*:*:*:*
  • OR cpe:/o:fedoraproject:fedora:33:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    opensmtpd opensmtpd 6.8.0 -
    opensmtpd opensmtpd *
    opensmtpd opensmtpd 6.8.0 patch1-rc1
    fedoraproject fedora 32
    fedoraproject fedora 33