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.
{
"cna_assigner": "mitre",
"cwe_ids": [
"CWE-1284"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77640.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"introduced": "0.2.6.1-alpha"
},
{
"fixed": "0.4.9.9"
}
],
"source": "AFFECTED_FIELD"
},
{
"extracted_events": [
{
"introduced": "0.2.6.1-alpha"
},
{
"fixed": "0.4.9.9"
}
],
"source": "CPE_FIELD"
},
{
"extracted_events": [
{
"fixed": "0.4.9.9"
}
],
"source": "DESCRIPTION"
}
]
}{
"cpe": "cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "0.4.9.9"
}
],
"source": "CPE_RANGE"
}