The build_tablename function in pgsql.c in the PostgreSQL (aka pgsql) extension in PHP through 5.6.7 does not validate token extraction for table names, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted name.
The BEGIN regular expression in the awk script detector in magic/Magdir/commands in file before 5.15 uses multiple wildcards with unlimited repetitions, which allows context-dependent attackers to cause a denial of service (CPU consumption) via a crafted ASCII file that triggers a large amount of backtracking, as demonstrated via a file with many newline characters.
The GNU Multiple Precision Arithmetic Library (GMP) interfaces for PHP through 7.1.4 allow attackers to cause a denial of service (memory consumption and application crash) via operations on long strings. NOTE: the vendor disputes this, stating "There is no security issue here, because GMP safely aborts in case of an OOM condition. The only attack vector here is denial of service. However, if you allow attacker-controlled, unbounded allocations you have a DoS vector regardless of GMP's OOM behavior.
In PHP versions 7.3.x below 7.3.27, 7.4.x below 7.4.15 and 8.0.x below 8.0.2, when using SOAP extension to connect to a SOAP server, a malicious SOAP server could return malformed XML data as a response that would cause PHP to access a null pointer and thus cause a crash.
ext/wddx/wddx.c in PHP before 5.6.25 and 7.x before 7.0.10 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) or possibly have unspecified other impact via an invalid wddxPacket XML document that is mishandled in a wddx_deserialize call, as demonstrated by a stray element inside a boolean element, leading to incorrect pop processing.
The xsl_ext_function_php function in ext/xsl/xsltprocessor.c in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13, when libxml2 before 2.9.2 is used, does not consider the possibility of a NULL valuePop return value before proceeding with a free operation during initial error checking, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted XML document, a different vulnerability than CVE-2015-6838.