SendmailCVEs & Vulnerabilities

sendmail through 8.17.2 allows SMTP smuggling in certain configurations. Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because sendmail supports <LF>.<CR><LF> but some other popular e-mail servers do not. This is resolved in 8.18 and later versions with 'o' in srv_features.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

The sm_close_on_exec function in conf.c in sendmail before 8.14.9 has arguments in the wrong order, and consequently skips setting expected FD_CLOEXEC flags, which allows local users to access unintended high-numbered file descriptors via a custom mail-delivery program.

sendmail before 8.14.4 does not properly handle a '\0' character in a Common Name (CN) field of an X.509 certificate, which (1) allows man-in-the-middle attackers to spoof arbitrary SSL-based SMTP servers via a crafted server certificate issued by a legitimate Certification Authority, and (2) allows remote attackers to bypass intended access restrictions via a crafted client certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Heap-based buffer overflow in Sendmail before 8.13.2 allows remote attackers to cause a denial of service (daemon crash) and possibly execute arbitrary code via a long X- header, as demonstrated by an X-Testing header.

Unspecified vulnerability in HP-UX B.11.00 and B.11.11, when running sendmail 8.9.3 or 8.11.1; and HP-UX B.11.23 when running sendmail 8.11.1; allows remote attackers to cause a denial of service via unknown attack vectors. NOTE: due to the lack of details from HP, it is not known whether this issue is a duplicate of another CVE such as CVE-2006-1173 or CVE-2006-4434.

The version of Sendmail 8.13.1-2 on Red Hat Enterprise Linux 4 Update 4 and earlier does not allow the administrator to disable SSLv2 encryption, which could cause less secure channels to be used than desired.

The version of Sendmail 8.13.1-2 on Red Hat Enterprise Linux 4 Update 4 and earlier does not reject the "localhost.localdomain" domain name for e-mail messages that come from external hosts, which might allow remote attackers to spoof messages.

Use-after-free vulnerability in Sendmail before 8.13.8 allows remote attackers to cause a denial of service (crash) via a long "header line", which causes a previously freed variable to be referenced. NOTE: the original developer has disputed the severity of this issue, saying "The only denial of service that is possible here is to fill up the disk with core dumps if the OS actually generates different core dumps (which is unlikely)... the bug is in the shutdown code (finis()) which leads directly to exit(3), i.e., the process would terminate anyway, no mail delivery or receiption is affected."

Sendmail before 8.13.7 allows remote attackers to cause a denial of service via deeply nested, malformed multipart MIME messages that exhaust the stack during the recursive mime8to7 function for performing 8-bit to 7-bit conversion, which prevents Sendmail from delivering queued messages and might lead to disk consumption by core dump files.

Signal handler race condition in Sendmail 8.13.x before 8.13.6 allows remote attackers to execute arbitrary code by triggering timeouts in a way that causes the setjmp and longjmp function calls to be interrupted and modify unexpected memory locations.

The ClamAV Mail fILTER (clamav-milter) 0.84 through 0.85d, when used in Sendmail using long timeouts, allows remote attackers to cause a denial of service by keeping an open connection, which prevents ClamAV from reloading.

The DNS map code in Sendmail 8.12.8 and earlier, when using the "enhdnsbl" feature, does not properly initialize certain data structures, which allows remote attackers to cause a denial of service (process crash) via an invalid DNS response that causes Sendmail to free incorrect data.

The prescan function in Sendmail 8.12.9 allows remote attackers to execute arbitrary code via buffer overflow attacks, as demonstrated using the parseaddr function in parseaddr.c.

A "potential buffer overflow in ruleset parsing" for Sendmail 8.12.9, when using the nonstandard rulesets (1) recipient (2), final, or (3) mailer-specific envelope recipients, has unknown consequences.

The Sendmail 8.12.3 package in Debian GNU/Linux 3.0 does not securely create temporary files, which could allow local users to gain additional privileges via (1) expn, (2) checksendmail, or (3) doublebounce.pl.

The prescan() function in the address parser (parseaddr.c) in Sendmail before 8.12.9 does not properly handle certain conversions from char and int types, which can cause a length check to be disabled when Sendmail misinterprets an input value as a special "NOCHAR" control value, allowing attackers to cause a denial of service and possibly execute arbitrary code via a buffer overflow attack using messages, a different vulnerability than CVE-2002-1337.

Buffer overflow in Sendmail 5.79 to 8.12.7 allows remote attackers to execute arbitrary code via certain formatted address fields, related to sender and recipient header comments as processed by the crackaddr function of headers.c.

Sendmail 8.9.0 through 8.12.6 allows remote attackers to bypass relaying restrictions enforced by the 'check_relay' function by spoofing a blank DNS hostname.

Sendmail 8.12.0 through 8.12.6 truncates log messages longer than 100 characters, which allows remote attackers to prevent the IP address from being logged via a long IDENT response.

Sendmail 8.9.0 through 8.12.3 allows local users to cause a denial of service by obtaining an exclusive lock on the (1) alias, (2) map, (3) statistics, and (4) pid files.

Sendmail Consortium's Restricted Shell (SMRSH) in Sendmail 8.12.6, 8.11.6-15, and possibly other versions after 8.11 from 5/19/1998, allows attackers to bypass the intended restrictions of smrsh by inserting additional commands after (1) "||" sequences or (2) "/" characters, which are not properly filtered or verified.

Buffer overflow in Sendmail before 8.12.5, when configured to use a custom DNS map to query TXT records, allows remote attackers to cause a denial of service and possibly execute arbitrary code via a malicious DNS server.

Sendmail before 8.12.1 does not properly drop privileges when the -C option is used to load custom configuration files, which allows local users to gain privileges via malformed arguments in the configuration file whose names contain characters with the high bit set, such as (1) macro names that are one character long, (2) a variable setting which is processed by the setoption function, or (3) a Modifiers setting which is processed by the getmodifiers function.

Sendmail before 8.12.1, without the RestrictQueueRun option enabled, allows local users to cause a denial of service (data loss) by (1) setting a high initial message hop count option (-h), which causes Sendmail to drop queue entries, (2) via the -qR option, or (3) via the -qS option.

Sendmail before 8.12.1, without the RestrictQueueRun option enabled, allows local users to obtain potentially sensitive information about the mail queue by setting debugging flags to enable debug mode.

Sendmail 8.10.0 through 8.11.5, and 8.12.0 beta, allows local users to modify process memory and possibly gain privileges via a large value in the 'category' part of debugger (-d) command line arguments, which is interpreted as a negative number.

Sendmail before 8.11.4, and 8.12.0 before 8.12.0.Beta10, allows local users to cause a denial of service and possibly corrupt the heap and gain privileges via race conditions in signal handlers.

Multiple unspecified vulnerabilities in sendmail 5, as installed on Sun SunOS 4.1.3_U1 and 4.1.4, have unspecified attack vectors and impact. NOTE: this might overlap CVE-1999-0129.

Sendmail before 8.10.0 allows remote attackers to cause a denial of service by sending a series of ETRN commands then disconnecting from the server, while Sendmail continues to process the commands after the connection has been terminated.

Denial of service in HP-UX sendmail 8.8.6 related to accepting connections.

Sendmail before 8.6.7 allows local users to gain root access via a large value in the debug (-d) command line option.

SunOS sendmail 5.59 through 5.65 uses popen to process a forwarding host argument, which allows local users to gain root privileges by modifying the IFS (Internal Field Separator) variable and passing crafted values to the -oR option.