Description
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.
Published: 2026-08-20
Score: 3.7 Low
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 20 Aug 2026 21:15:00 +0000

Type Values Removed Values Added
Description 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.
First Time appeared Torproject
Torproject tor
Weaknesses CWE-1284
CPEs cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
Vendors & Products Torproject
Torproject tor
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Subscriptions

Torproject Tor
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-08-20T21:02:36.470Z

Reserved: 2026-08-20T21:02:36.115Z

Link: CVE-2026-77640

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-20T21:17:11.373

Modified: 2026-08-20T21:17:11.373

Link: CVE-2026-77640

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses