CVE-2019-9023

An issue was discovered in PHP before 5.6.40, 7.x before 7.1.26, 7.2.x before 7.2.14, and 7.3.x before 7.3.1. A number of heap-based buffer over-read instances are present in mbstring regular expression functions when supplied with invalid multibyte data. These occur in ext/mbstring/oniguruma/regcomp.c, ext/mbstring/oniguruma/regexec.c, ext/mbstring/oniguruma/regparse.c, ext/mbstring/oniguruma/enc/unicode.c, and ext/mbstring/oniguruma/src/utf32_be.c when a multibyte regular expression pattern contains invalid multibyte sequences.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name	Vendor	Start Version	End Version
Php	Php	*	5.6.40 (excluding)
Php	Php	7.0.0 (including)	7.1.26 (excluding)
Php	Php	7.2.0 (including)	7.2.14 (excluding)
Php	Php	7.3.0 (including)	7.3.1 (excluding)
Red Hat Enterprise Linux 8	RedHat	php:7.2-8020020191108065827.2c7ca891	*
Red Hat Software Collections for Red Hat Enterprise Linux 7	RedHat	rh-php71-php-0:7.1.30-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7	RedHat	rh-php72-php-0:7.2.24-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS	RedHat	rh-php71-php-0:7.1.30-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS	RedHat	rh-php71-php-0:7.1.30-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS	RedHat	rh-php72-php-0:7.2.24-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS	RedHat	rh-php71-php-0:7.1.30-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS	RedHat	rh-php72-php-0:7.2.24-1.el7	*
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS	RedHat	rh-php72-php-0:7.2.24-1.el7	*
Php5	Ubuntu	trusty	*
Php7.0	Ubuntu	xenial	*
Php7.2	Ubuntu	bionic	*
Php7.2	Ubuntu	cosmic	*
Php7.2	Ubuntu	devel	*
Php7.2	Ubuntu	upstream	*
Php7.3	Ubuntu	upstream	*

Potential Mitigations

Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

https://cwe.mitre.org/data/definitions/540.html

NVD	https://nvd.nist.gov/vuln/detail/CVE-2019-9023
CWE	https://cwe.mitre.org/data/definitions/125.html

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

References

CVE-2019-9023

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References