CVE-2026-77640tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- Weakness (CWE)
- CWE-1284
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mitre
- NVD analysis
- Analyzed
- Record last updated
- Aug 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
torproject Tor torproject:tor (from the name) | from 0.2.6.1-alpha before 0.4.9.9 | CNA record |
torproject tor torproject:tor | before 0.4.9.9 | NVD |
References
- https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLogpermissions-required, release-notes, vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.