CVE-2026-77640: tor before 0.4.9.9 (exclusive); +1 more affected products

CVE-2026-77640. CVSS 3.1 base score 5.3 (MEDIUM, NVD). EPSS 0.00378 (percentile 0.30202), scored 17-Oct-2026.

Affected technology

tor · before 0.4.9.9 (exclusive)
torproject

Tor · 0.2.6.1-alpha to before 0.4.9.9
torproject

Description’s affected range: before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1

Component: Not specified by the source

Attack conditions (Vendor/CNA, CVSS 3.1): Network (remote) · No privileges required · No user interaction required

Attack conditions (NVD, CVSS 3.1): Network (remote) · No privileges required · No user interaction required

What an attacker can do

Vendor/CNA’s CVSS 3.1 assessment (base score 3.7/10) rates confidentiality and integrity impact as none; availability impact as low. NVD’s CVSS 3.1 assessment (base score 5.3/10) rates confidentiality and integrity impact as none; availability impact as low. The description does not specify what an attacker can achieve beyond these rated impacts.

Published 18-Oct-2026 20:24 UTC

CWE: CWE-1284
CCR priority: 21.3 /100 (P4)
CVSS 3.1: 5.3 /10 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L · NVD
EPSS: 0.00378 · percentile 0.30202 · 2026-10-17
KEV: no

Provenance

NVD CVE API 2.0 · Source record · observed 2026-10-18 20:23:06.032219+00:00 UTC

Stable permalink: https://cybercodered.org/item/cve-cve-2026-77640.html