GHSA-7c26-995w-6f47: veraPDF Parser DoS via PostScript Type 1 Font Programs

Summary Description A PostScript-interpreter-driven Denial of Service (CWE-1325) vulnerability in veraPDF allows a remote attacker to exhaust validator memory or CPU by submitting a PDF whose Type 1 font /FontFile is a font program containing attacker-supplied PostScript. veraPDF's Type 1 font program parser dispatches every cleartext token through a hardcoded operator allow-list whose members include the unbounded array N allocation operator and the for control operator with no zero-increment guard. This affects all current versions of veraPDF-parser. Details The vulnerability resides in veraPDF-parser. Type 1 font program streams referenced from any Type 1 font's /FontDescriptor /FontFile are parsed by Type1FontProgram (veraPDF-parser/src/main/java/org/verapdf/pd/font/type1/Type1FontProgram.java), which extends PSParser. parseFont reads cleartext PostScript tokens until it encounters eexec (which switches into the encrypted private dictionary parser) or end-of-stream. Each non-eexec token is dispatched via toExecute, which gates execution behind a hardcoded allow-list. The allow-list explicitly admits both ARRAY (Type1FontProgram.java:98) and FOR (Type1FontProgram.java:100). When either keyword passes the gate, operator.execute delegates straight into the generic PSOperator implementation (org.verapdf.parser.postscript.PSOperator, methods array() at PSOperator.java:536-547 and opFor() at PSOperator.java:571-592), which apply no validation: 1. array N calls COSArray.construct(N) followed by new ArrayList<>(N) (COSArray.java:102), so the underlying Object[] is allocated up-front. Passing 2147483647 (Integer.MAX_VALUE) requests a 16 GB backing array on a 64-bit JVM. 2. for runs for (long i = initial; i <= limit; i += increment) with no validation of increment. With increment == 0, the loop never exits. In addition to the two shared primitives, toExecute introduces a third primitive specific to this code path: when an unknown operator is encountered, it looks t