CVE-2026-77639

Published Aug 20, 2026

Last updated 3 days ago

CVSS medium 5.3

Overview

Description
Tor before 0.4.9.9 was prone to a compression bomb bypass where an attacker could concatenate many gzip or zlib sub-streams, each just under the per-stream detection threshold, to avoid the compression bomb check entirely. This is TROVE-2026-022.
Source
cve@mitre.org
NVD status
Received

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.3
Impact score
1.4
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Severity
MEDIUM

Weaknesses

cve@mitre.org
CWE-420

Social media

Hype score
Not currently trending

  1. CVE-2026-77639 Tor Compression Bomb Bypass Vulnerability (TROVE-2026-022) https://t.co/noEAcUxRwu

    @VulmonFeeds

    20 Aug 2026

    117 Impressions

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References

Sources include official advisories and independent security research.