CVE-2026-77640 (GCVE-0-2026-77640)
Vulnerability from cvelistv5 – Published: 2026-08-20 21:02 – Updated: 2026-08-21 20:08
VLAI
EPSS
VEX
Summary
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.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-21 19:51 UTC
CWE
- CWE-1284 - Improper Validation of Specified Quantity in Input
Assigner
References
1 reference
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| torproject | Tor |
Affected:
0.2.6.1-alpha , < 0.4.9.9
(custom)
cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:* |
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Sightings
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Nomenclature
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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