GNU Aspell vulnerabilities

GNU Aspell contains an integer truncation vulnerability in the WritableDict::add() function in modules/speller/default/writable.cpp. When loading a personal wordlist, the word length is stored as a single byte, causing truncation for words whose length is a multiple of 256, leading to heap corruption. An attacker can exploit this by convincing a user to run aspell with a crafted personal wordlist containing such a word, resulting in denial of service. This issue was fixed in commit 782ce94e4dc71eaec4ee1bd945eb3b9c47c5387d, which will be released in version 0.60.8.3.

GNU Aspell contains an out-of-bounds read vulnerability in ReadOnlyDict::load() in readonly_ws.cpp. When loading a binary .rws dictionary file, it uses offset fields from the file header as byte indices into a heap buffer without validating their bounds. An attacker can trigger this by convincing a user to run aspell with a crafted dictionary file supplied through --master, --dict-dir, or configuration options, leading to heap memory disclosure or a denial of service via application crash.

GNU Aspell prezip-bin contains a heap-based buffer overflow vulnerability in the decompressor in prog/prezip.c. The decompressor does not properly check buffer space, so a crafted compressed file can cause out-of-bounds read and write operations on the heap. An attacker who convinces a user to process a malicious compressed file with prezip-bin can trigger memory corruption, leading to a process crash.

GNU Aspell 0.60.8.2 (first vulnerable version is not known) contains a heap-based buffer overflow write (CWE-122) in its read-only dictionary loader. String::reserve() in common/string.hpp computes its capacity check with a signed int ((int)s + 1), so a requested size of 0x7FFFFFFF wraps negative and the backing buffer is never grown. ReadOnlyDict::load() in modules/speller/default/readonly_ws.cpp passes the unvalidated 32-bit size fields from a .rws dictionary header into this path, so a crafted .rws file with a valid endian marker (12345678) and an oversized length field (e.g. lang_name_size = 0x7FFFFFFF) causes attacker-controlled data to be written out of bounds past an undersized heap allocation. An attacker who induces a victim to load a malicious dictionary — for example via aspell dump master <file> — can corrupt heap memory, resulting in denial of service and potentially code execution. Fixed in b830b6e and will be fixed in release 0.60.8.3.