Tor

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.

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)…

Tor before 0.4.9.7 has an out-of-bounds read by one byte via a malformed BEGIN cell, aka TROVE-2026-007.

Tor before 0.4.9.7 has a NULL pointer dereference when a CERT cell is received out of order, aka TROVE-2026-006.

Tor before 0.4.9.7, when circuit queue memory pressure exists, can experience a client crash because of a double close of a circuit, aka TROVE-2026-009.

Tor before 0.4.9.7 mishandles accounting of the conflux out-of-order queue during the clearing of a queue, aka TROVE-2026-010.

Tor before 0.4.9.7 can attempt or accept BEGIN_DIR via conflux legs, aka TROVE-2026-008.

Tor before 0.4.9.7 has an out-of-bounds read when an END, a TRUNCATE, or a TRUNCATED cell lacks a reason in its payload, aka TROVE-2026-011.

A security flaw has been discovered in Tor up to 0.4.7.16/0.4.8.17. Impacted is an unknown function of the component Onion Service Descriptor Handler. Performing manipulation results in resource consumption. The attack may be initiated remotely. The attack's complexity is rated…

Tor before 0.1.2.16, when ControlPort is enabled, does not properly restrict commands to localhost port 9051, which allows remote attackers to modify the torrc configuration file, compromise anonymity, and have other unspecified impact via HTTP POST data containing commands…

Heap-based buffer overflow in Tor before 0.2.1.28 and 0.2.2.x before 0.2.2.20-alpha allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via unspecified vectors.

The SafeSocks option in Tor before 0.4.7.13 has a logic error in which the unsafe SOCKS4 protocol can be used but not the safe SOCKS4a protocol, aka TROVE-2022-002.

Tor 0.4.7.x before 0.4.7.8 allows a denial of service via the wedging of RTT estimation.

Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7 mishandles the relationship between batch-signature verification and single-signature verification, leading to a remote assertion failure, aka TROVE-2021-007.

An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-006. The v3 onion service descriptor parsing allows out-of-bounds memory access, and a client crash, via a crafted onion service descriptor

An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-005. Hashing is mishandled for certain retrieval of circuit data. Consequently. an attacker can trigger the use of an attacker-chosen circuit ID to cause algorithm inefficiency.

An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-003. An attacker can forge RELAY_END or RELAY_RESOLVED to bypass the intended access control for ending a stream.

Tor before 0.4.5.7 allows a remote attacker to cause Tor directory authorities to exit with an assertion failure, aka TROVE-2021-002.

Tor before 0.4.3.6 has an out-of-bounds memory access that allows a remote denial-of-service (crash) attack against Tor instances built to use Mozilla Network Security Services (NSS), aka TROVE-2020-001.

Tor before 0.3.5.10, 0.4.x before 0.4.1.9, and 0.4.2.x before 0.4.2.7 allows remote attackers to cause a Denial of Service (memory leak), aka TROVE-2020-004. This occurs in circpad_setup_machine_on_circ because a circuit-padding machine can be negotiated twice on the same…

Tor before 0.3.5.10, 0.4.x before 0.4.1.9, and 0.4.2.x before 0.4.2.7 allows remote attackers to cause a Denial of Service (CPU consumption), aka TROVE-2020-002.

The daemon in Tor through 0.4.1.8 and 0.4.2.x through 0.4.2.6 does not verify that a rendezvous node is known before attempting to connect to it, which might make it easier for remote attackers to discover circuit information. NOTE: The network team of Tor claims this is an…

buf_pullup in Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 does not properly handle unexpected arrival times of buffers with invalid layouts, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via crafted packets.

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) 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.

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.

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.

Tor before 0.2.4.23 and 0.2.5 before 0.2.5.6-alpha maintains a circuit after an inbound RELAY_EARLY cell is received by a client, which makes it easier for remote attackers to conduct traffic-confirmation attacks by using the pattern of RELAY and RELAY_EARLY cells as a means of…

Tor before 0.2.3.24-rc allows remote attackers to cause a denial of service (assertion failure and daemon exit) by performing link protocol negotiation incorrectly.

Tor before 0.2.3.23-rc allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a renegotiation attempt that occurs after the initiation of the V3 link protocol.

Tor before 0.2.4.20, when OpenSSL 1.x is used in conjunction with a certain HardwareAccel setting on Intel Sandy Bridge and Ivy Bridge platforms, does not properly generate random numbers for (1) relay identity keys and (2) hidden-service identity keys, which might make it…

The connection_edge_process_relay_cell function in or/relay.c in Tor before 0.2.3.25 maintains circuits even if an unexpected SENDME cell arrives, which might allow remote attackers to cause a denial of service (memory consumption or excessive cell reception rate) or bypass…

The tor_timegm function in common/util.c in Tor before 0.2.2.39, and 0.2.3.x before 0.2.3.22-rc, does not properly validate time values, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a malformed directory object, a different…

The compare_tor_addr_to_addr_policy function in or/policies.c in Tor before 0.2.2.39, and 0.2.3.x before 0.2.3.21-rc, allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a zero-valued port field that is not properly handled during policy…

routerlist.c in Tor before 0.2.2.38 uses a different amount of time for relay-list iteration depending on which relay is chosen, which might allow remote attackers to obtain sensitive information about relay selection via a timing side-channel attack.

The networkstatus_parse_vote_from_string function in routerparse.c in Tor before 0.2.2.38 does not properly handle an invalid flavor name, which allows remote attackers to cause a denial of service (out-of-bounds read and daemon crash) via a crafted (1) vote document or (2)…

Use-after-free vulnerability in dns.c in Tor before 0.2.2.38 might allow remote attackers to cause a denial of service (daemon crash) via vectors related to failed DNS requests.

Tor before 0.2.2.25-alpha, when configured as a relay without the Nickname configuration option, uses the local hostname as the Nickname value, which allows remote attackers to obtain potentially sensitive information by reading this value.

Tor before 0.2.2.24-alpha continues to use a reachable bridge that was previously configured but is not currently configured, which might allow remote attackers to obtain sensitive information about clients in opportunistic circumstances by monitoring network traffic to the…

Tor before 0.2.2.34, when configured as a bridge, sets up circuits through a process different from the process used by a client, which makes it easier for remote attackers to enumerate bridges by observing circuit building.

Tor before 0.2.2.34, when configured as a bridge, uses direct DirPort access instead of a Tor TLS connection for a directory fetch, which makes it easier for remote attackers to enumerate bridges by observing DirPort connections.

Multiple heap-based buffer overflows in Tor before 0.2.2.35 allow remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code by (1) establishing a SOCKS connection to SocksPort or (2) leveraging a SOCKS proxy configuration.

Tor before 0.2.2.34, when configured as a bridge, accepts the CREATE and CREATE_FAST values in the Command field of a cell within an OR connection that it initiated, which allows remote relays to enumerate bridges by using these values.

Tor before 0.2.2.34, when configured as a client or bridge, sends a TLS certificate chain as part of an outgoing OR connection, which allows remote relays to bypass intended anonymity properties by reading this chain and then determining the set of entry guards that the client…

Buffer overflow in the policy_summarize function in or/policies.c in Tor before 0.2.1.30 allows remote attackers to cause a denial of service (directory authority crash) via a crafted policy that triggers creation of a long port list.

Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha might allow remote attackers to cause a denial of service (assertion failure and daemon exit) via vectors related to malformed router caches and improper handling of integer values.

Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha allows remote attackers to cause a denial of service (assertion failure and daemon exit) via blobs that trigger a certain file size, as demonstrated by the cached-descriptors.new file.

The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow…

Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha makes calls to Libevent within Libevent log handlers, which might allow remote attackers to cause a denial of service (daemon crash) via vectors that trigger certain log messages.

Heap-based buffer overflow in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.