Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 does not properly handle pending-connection resolve states during periods of high DNS load, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via crafted packets.
The Hidden Service (HS) server implementation in Tor before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via unspecified vectors.
The Hidden Service (HS) client implementation in Tor before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7 allows remote servers to cause a denial of service (assertion failure and application exit) via a malformed HS descriptor.
In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, remote denial of service against Tor clients and relays can occur via memory exhaustion in the KIST cell scheduler.
A use-after-free vulnerability in SVG Animation has been discovered. An exploit built on this vulnerability has been discovered in the wild targeting Firefox and Tor Browser users on Windows. This vulnerability affects Firefox < 50.0.2, Firefox ESR < 45.5.1, and Thunderbird < 45.5.1.
An issue was discovered in Tor before 0.2.9.15, 0.3.1.x before 0.3.1.10, and 0.3.2.x before 0.3.2.10. The directory-authority protocol-list subprotocol implementation allows remote attackers to cause a denial of service (NULL pointer dereference and directory-authority crash) via a misformatted relay descriptor that is mishandled during voting.
A use-after-free issue was discovered in Tor 0.3.2.x before 0.3.2.10. It allows remote attackers to cause a denial of service (relay crash) because the KIST implementation allows a channel to be added more than once in the pending list.
Tor Browser before 7.0.9 on macOS and Linux allows remote attackers to bypass the intended anonymity feature and discover a client IP address via vectors involving a crafted web site that leverages file:// mishandling in Firefox, aka TorMoil. NOTE: Tails is unaffected.
The rend_service_intro_established function in or/rendservice.c in Tor before 0.2.8.15, 0.2.9.x before 0.2.9.12, 0.3.0.x before 0.3.0.11, 0.3.1.x before 0.3.1.7, and 0.3.2.x before 0.3.2.1-alpha, when SafeLogging is disabled, allows attackers to obtain sensitive information by leveraging access to the log files of a hidden service, because uninitialized stack data is included in an error message about construction of an introduction point circuit.