GNU patch through 2.7.6 contains a free(pline[pend]) Double Free vulnerability in the function anotherhunk in pch.c that can cause a denial of service via a crafted patch file. NOTE: this issue exists because of an incomplete fix for CVE-2018-6952.

A double free exists in the anotherhunk function in pch.c in GNU patch through 2.7.6.

An issue was discovered in GNU patch through 2.7.6. There is a segmentation fault, associated with a NULL pointer dereference, leading to a denial of service in the intuitdifftype function in pch.c, aka a "mangled rename" issue.

GNU patch does not properly sanitize patch files allowing for malicious patches to pass arbitrary shell commands to ed. An attacker could exploit this by tricking a user into applying malicious patches with the patch command.

A vulnerability was found in GNU patch through 2.7.6 is vulnerable to OS shell command injection that can be exploited by opening a crafted patch file that contains an ed style diff payload with shell metacharacters. The ed editor does not need to be present on the vulnerable system. This is different from CVE-2018-1000156.

Reference: https://git.savannah.gnu.org/cgit/patch.git/commit/?id=3fcd042d26d70856e826a42b5f93dc4854d80bf0

In GNU patch through 2.7.6, the following of symlinks is mishandled in certain cases other than input files. This affects inp.c and util.c.

A vulnerability was found in doedscript in pch.c in GNU patch through 2.7.6 does not block strings beginning with a ! character. NOTE: this is the same commit as for CVE-2019-13638, but the ! syntax is specific to ed, and is unrelated to a shell metacharacter.

Reference: https://git.savannah.gnu.org/cgit/patch.git/commit/?id=3fcd042d26d70856e826a42b5f93dc4854d80bf0 https://seclists.org/bugtraq/2019/Aug/29