CVE-2026-77640

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.

Affected Software

VendorProductVersion RangeStatus
torprojectTor0.2.6.1-alpha < 0.4.9.9affected

Weaknesses

  • CWE-1284: CWE-1284 Improper Validation of Specified Quantity in Input

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References