In Xpdf 4.02, SplashOutputDev::endType3Char(GfxState *state) SplashOutputDev.cc:3079 is trying to use the freed `t3GlyphStack->cache`, which causes an `heap-use-after-free` problem. The codes of a previous fix for nested Type 3 characters wasn't correctly handling the case where a Type 3 char referred to another char in the same Type 3 font.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://forum.xpdfreader.com/viewtopic.php?f=3&t=41915 | exploit vendor advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-25725 | issue tracking exploit third party advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ZUU5QG6SSVRTKZTR3A72LDRVZETEI63/ | mailing list third party advisory vendor advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VLOYVJSM54IL6I5RY4QTJGRS7PIEG44X/ | mailing list third party advisory vendor advisory |