What is GHSA-5g6h-2vr8-m7f4?

GHSA-5g6h-2vr8-m7f4 is a security advisory published by GitHub Security Advisories with Low severity. tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream...

Which CVE IDs does GHSA-5g6h-2vr8-m7f4 cover?

GHSA-5g6h-2vr8-m7f4 covers the following CVE IDs: CVE-2026-77640. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-5g6h-2vr8-m7f4?

GHSA-5g6h-2vr8-m7f4 has a CVSS v3 base score of 3.7, published by GitHub Security Advisories.

GHSA-5g6h-2vr8-m7f4LowCVSS 3.7

tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream...

Vendor

GitHub Security Advisories

Published

August 20, 2026

Last Modified

August 20, 2026

🔗 CVE IDs covered (1)

CVE-2026-77640 →

📋 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.

🔗 References (3)

https://nvd.nist.gov/vuln/detail/CVE-2026-77640
https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog
https://github.com/advisories/GHSA-5g6h-2vr8-m7f4