USN-4934-1: Exim vulnerabilities

It was discovered that Exim contained multiple security issues. An attacker could use these issues to cause a denial of service, execute arbitrary code remotely, obtain sensitive information, or escalate local privileges...

CVE-2020-28021

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newline characters into a spool file which indirectly leads to remote code execution as root via AUTH= in a MAIL FROM command...

CVE-2020-28009

Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow because getstdinput allows unbounded reads that are accompanied by unbounded increases in a certain size variable. NOTE: exploitation may be impractical because of the execution time needed to overflow multiple days...

CVE-2020-28020

Exim 4 before 4.92 allows Integer Overflow to Buffer Overflow, in which an unauthenticated remote attacker can execute arbitrary code by leveraging the mishandling of continuation lines during header-length restriction...

CVE-2020-28025

Exim 4 before 4.94.2 allows Out-of-bounds Read because pdkimfinishbodyhash does not validate the relationship between sig-bodyhash.len and b-bh.len; thus, a crafted DKIM-Signature header might lead to a leak of sensitive information from process memory...

CVE-2020-28014

Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. The -oP option is available to the exim user, and allows a denial of service because root-owned files can be overwritten...

CVE-2020-28024

Exim 4 before 4.94.2 allows Buffer Underwrite that may result in unauthenticated remote attackers executing arbitrary commands, because smtpungetc was only intended to push back characters, but can actually push back non-character error codes such as EOF...

CVE-2020-28018

Exim 4 before 4.94.2 allows Use After Free in smtpreset in certain situations that may be common for builds with OpenSSL...

UBUNTU-CVE-2020-28021

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newline characters into a spool file which indirectly leads to remote code execution as root via AUTH= in a MAIL FROM command...

UBUNTU-CVE-2021-27216

Exim 4 before 4.94.2 has Execution with Unnecessary Privileges. By leveraging a deletepidfile race condition, a local user can delete arbitrary files as root. This involves the -oP and -oPX options...

UBUNTU-CVE-2020-28012

Exim 4 before 4.94.2 allows Exposure of File Descriptor to Unintended Control Sphere because rdainterpret uses a privileged pipe that lacks a close-on-exec flag...

CVE-2020-28013

Exim 4 before 4.94.2 allows Heap-based Buffer Overflow because it mishandles "-F '.'" on the command line, and thus may allow privilege escalation from any user to root. This occurs because of the interpretation of negative sizes in strncpy...

UBUNTU-CVE-2020-28010

Exim 4 before 4.94.2 allows Out-of-bounds Write because the main function, while setuid root, copies the current working directory pathname into a buffer that is too small on some common platforms...

UBUNTU-CVE-2020-28022

Exim 4 before 4.94.2 has Improper Restriction of Write Operations within the Bounds of a Memory Buffer. This occurs when processing name=value pairs within MAIL FROM and RCPT TO commands...

UBUNTU-CVE-2020-28007

Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the log directory owned by a non-root user, a symlink or hard link attack allows overwriting critical root-owned files anywhere on the filesystem...

UBUNTU-CVE-2020-28011

Exim 4 before 4.94.2 allows Heap-based Buffer Overflow in queuerun via two sender options: -R and -S. This may cause privilege escalation from exim to root...

CVE-2020-28008

Exim 4 before 4.94.2 allows Execution with Unnecessary Privileges. Because Exim operates as root in the spool directory owned by a non-root user, an attacker can write to a /var/spool/exim4/input spool header file, in which a crafted recipient address can indirectly lead to command execution...

CVE-2020-28019

Exim 4 before 4.94.2 has Improper Initialization that can lead to recursion-based stack consumption or other consequences. This occurs because use of certain getc functions is mishandled when a client uses BDAT instead of DATA...

CVE-2020-28011

Exim 4 before 4.94.2 allows Heap-based Buffer Overflow in queuerun via two sender options: -R and -S. This may cause privilege escalation from exim to root...

CVE-2020-28026

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters, relevant in non-default configurations that enable Delivery Status Notification DSN. Certain uses of ORCPT= can place a newline into a spool header file, and indirectly allow unauthenticated remote attackers to execute arbitrary...