Name: CVE-2026-77640: Improper Validation of Specified Quantity in Input
Creator: Rapid7
Published: 2026-08-20T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-77640, CWE-1284, CVSS 5.3, EPSS 0.00378

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.

CVSS Details

CVSS 3.1 Base Score: 5.3
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Debian	—	Upgrade tor	Aug 23, 2026	Aug 23, 2026

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CVSS Details

Covered by Rapid7

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