tor: tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1
CVE-2026-77640 is fixed in tor on 1 platform, first by DEBIAN-CVE-2026-77640, released August 21, 2026. It is not reported as exploited. Patch Radar priority: Routine.
tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1. A truncated stream never reaches Z_STREAM_END, causing zlib to return Z_BUF_ERROR with no input remaining, which buf_add_compress() mistook for a full output buffer and retried forever. Fixed by returning TOR_COMPRESS_ERROR in that case so the caller can abort cleanly. This is TROVE-2026-021.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| tor · Debian 12.15 (bookworm) | 0.4.9.9-1 | DEBIAN-CVE-2026-77640 | Aug 21, 2026 |
| tor · Debian 13.5 (trixie) | 0.4.9.11-0+deb13u1 | DEBIAN-CVE-2026-77640 | Aug 21, 2026 |
| tor · Debian 14 | 0.4.9.9-1 | DEBIAN-CVE-2026-77640 | Aug 21, 2026 |
Patch Radar data is free to use with attribution. Terms and how to credit it.
Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.