tls: Fix race condition in tls_sw_cancel_work_tx()

Summary

In the Linux kernel, the following vulnerability has been resolved: tls: Fix race condition in tls_sw_cancel_work_tx() This issue was discovered during a code audit. After cancel_delayed_work_sync() is called from tls_sk_proto_close(), tx_work_handler() can still be scheduled from paths such as the Delayed ACK handler or ksoftirqd. As a result, the tx_work_handler() worker may dereference a freed TLS object. The following is a simple race scenario: cpu0 cpu1 tls_sk_proto_close() tls_sw_cancel_work_tx() tls_write_space() tls_sw_write_space() if (!test_and_set_bit(BIT_TX_SCHEDULED, &tx_ctx->tx_bitmask)) set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask); cancel_delayed_work_sync(&ctx->tx_work.work); schedule_delayed_work(&tx_ctx->tx_work.work, 0); To prevent this race condition, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync().

Timeline

1. Mar 10, 2026, 5:28 PM UTCCVE published
2. Oct 16, 2026, 3:06 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: total

3. Oct 19, 2026, 6:35 PM UTCRecord last updated

Affected versions

• Linux Linux

  From f87e62d45e51b12d48d2cb46b5cde8f83b866bc4 · fixed in a5de36d6cee74a92c1a21b260bc507e64bc451de; From f87e62d45e51b12d48d2cb46b5cde8f83b866bc4 · fixed in 854cd32bc74fe573353095e90958490e4e4d641b; From f87e62d45e51b12d48d2cb46b5cde8f83b866bc4 · fixed in 17153f154f80be2b47ebf52840f2d8f724eb2f3b; From f87e62d45e51b12d48d2cb46b5cde8f83b866bc4 · fixed in 7bb09315f93dce6acc54bf59e5a95ba7365c2be4

• Linux Linux

  5.3

• KernelLinux

  From 5.3.0 · fixed in 6.12.75; From 6.13.0 · fixed in 6.18.16; From 6.19.0 · fixed in 6.19.6

References 4