CVE-2017-8819

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2017-12-03 · updated 2026-06-17

Description

In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, the replay-cache protection mechanism is ineffective for v2 onion services, aka TROVE-2017-009. An attacker can send many INTRODUCE2 cells to trigger this issue.

Affected products

Debian Linux: 8.0, 9.0
Tor Project Tor: before 0.2.5.16; from 0.2.6 before 0.2.8.17; from 0.2.9 before 0.2.9.14; from 0.3.0 before 0.3.0.13; from 0.3.1 before 0.3.1.9 — fixed in 0.2.5.16, 0.2.8.17, 0.2.9.14, 0.3.0.13, 0.3.1.9

How to fix

Upgrade to a fixed version: Tor Project Tor 0.2.5.16, 0.2.8.17, 0.2.9.14, 0.3.0.13. Check the vendor advisory for mitigations.

References

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