CVE-2026-62250

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CVE-2026-62250

Summary: LibreDWG: unbounded allocation in pre-R13 DWG entity decoding

Details: LibreDWG is a free C library to read and write DWG files. Prior to 0.14.8413, a crafted pre-R13 DWG can make `decode_preR13_entities()` in `src/decode.c` enter a nonterminating loop that allocates a new object each iteration. `decode_preR13` in `src/decode_r11.c` computes `size` from the raw file-controlled `entities_start` and `entities_end` header bounds; the callee clamps `end` to `dat->size` but never recalculates `size`. At `end` of input, `bit_read_RC` and `bit_read_RS` stop advancing `dat->byte`, the overflow guard fails because `end` equals `dat->size`, and the no-advance check compares against `oldpos` saved before the loop instead of the previous iteration. This leaves repeated allocation of `dwg->object` entries until allocation fails or the process is OOM-killed, not merely a constant-memory CPU hang. The defect remains after the clamping and no-progress changes associated with the earlier issue 1131. Applications and tools calling `dwg_read_file()` on untrusted files, including `dwg2dxf`, `dwgread` and `dwg2svg`, can suffer denial of service when a user or automated pipeline opens a malformed file; no attacker credentials are required. This issue is fixed in repository nightly version 0.14.8413.

References: https://github.com/LibreDWG/libredwg/releases/tag/0.14.8413, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62250.json, https://github.com/LibreDWG/libredwg/security/advisories/GHSA-7625-26gc-xqvp, https://nvd.nist.gov/vuln/detail/CVE-2026-62250, https://github.com/LibreDWG/libredwg/issues/1131, https://github.com/LibreDWG/libredwg/commit/4e14952c43be5b8feff6e54a61af3425d6ca95a4