{"cve":"CVE-2009-0654","nvd":{"published":"2009-02-20T19:30:00.313","modified":"2026-06-16T23:05:30.340","status":"Modified","description":"Tor 0.2.0.28, and probably 0.2.0.34 and earlier, allows remote attackers, with control of an entry router and an exit router, to confirm that a sender and receiver are communicating via vectors involving (1) replaying, (2) modifying, (3) inserting, or (4) deleting a single cell, and then observing cell recognition errors at the exit router.  NOTE: the vendor disputes the significance of this issue, noting that the product's design \"accepted end-to-end correlation as an attack that is too expensive to solve.\"","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["http://blog.torproject.org/blog/one-cell-enough","http://www.blackhat.com/html/bh-dc-09/bh-dc-09-archives.html#Fu","http://www.blackhat.com/presentations/bh-dc-09/Fu/BlackHat-DC-09-Fu-Break-Tors-Anonymity.pdf","http://blog.torproject.org/blog/one-cell-enough","http://www.blackhat.com/html/bh-dc-09/bh-dc-09-archives.html#Fu"],"products":["tor:tor"],"source":"nvd","synced_at":"2026-10-19T19:53:23.791937413+00:00"},"epss":{"cve":"CVE-2009-0654","score":0.02391,"percentile":0.83973,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}