# CVE-2026-31507: net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer CVE-2026-31507 is fixed in 12 products on 1 platform, first by DEBIAN-CVE-2026-31507, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-31507 - Priority: High - CVSS: 7.8 (Important) - EPSS: 0.0013 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 22, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31507 ## Description In the Linux kernel, the following vulnerability has been resolved: net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer smc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores the pointer in pipe_buffer.private. The pipe_buf_operations for these buffers used .get = generic_pipe_buf_get, which only increments the page reference count when tee(2) duplicates a pipe buffer. The smc_spd_priv pointer itself was not handled, so after tee() both the original and the cloned pipe_buffer share the same smc_spd_priv *. When both pipes are subsequently released, smc_rx_pipe_buf_release() is called twice against the same object: 1st call: kfree(priv) sock_put(sk) smc_rx_update_cons() [correct] 2nd call: kfree(priv) sock_put(sk) smc_rx_update_cons() [UAF] KASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which then escalates to a NULL-pointer dereference and kernel panic via smc_rx_update_consumer() when it chases the freed priv->smc pointer: BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0 Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74 Call Trace: dump_stack_lvl+0x53/0x70 print_report+0xce/0x650 kasan_report+0xc6/0x100 smc_rx_pipe_buf_release+0x78/0x2a0 free_pipe_info+0xd4/0x130 pipe_release+0x142/0x160 __fput+0x1c6/0x490 __x64_sys_close+0x4f/0x90 do_syscall_64+0xa6/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f BUG: kernel NULL pointer dereference, address: 0000000000000020 RIP: 0010:smc_rx_update_consumer+0x8d/0x350 Call Trace: smc_rx_pipe_buf_release+0x121/0x2a0 free_pipe_info+0xd4/0x130 pipe_release+0x142/0x160 __fput+0x1c6/0x490 __x64_sys_close+0x4f/0x90 do_syscall_64+0xa6/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception Beyond the memory-safety problem, duplicating an SMC splice buffer is semantically questionable: smc_rx_update_cons() would advance the consumer cursor twice for the same data, corrupting receive-window accounting. A refcount on smc_spd_priv could fix the double-free, but the cursor-accounting issue would still need to be addressed separately. The .get callback is invoked by both tee(2) and splice_pipe_to_pipe() for partial transfers; both will now return -EFAULT. Users who need to duplicate SMC socket data must use a copy-based read path. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-default sles 15.6 | 6.4.0-150600.23.112.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-default-base sles 15.6 | 6.4.0-150600.23.112.1.150600.12.52.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.55.1.150700.17.33.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-docs sles 15.6 | 6.4.0-150600.23.112.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-livepatch-SLE15-SP6_Update_26 sles 15.6 | 1-150600.13.3.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_15 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-obs-build sles 15.6 | 6.4.0-150600.23.112.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-source sles 15.6 | 6.4.0-150600.23.112.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-syms sles 15.6 | 6.4.0-150600.23.112.1 | [SUSE-SU-2026:2195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2195-1.md) | Jul 1, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.55.1 | [SUSE-SU-2026:2238-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2238-1.md) | Jun 30, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.170-1 | [DEBIAN-CVE-2026-31507](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31507.md) | May 15, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.85-1 | [DEBIAN-CVE-2026-31507](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31507.md) | May 15, 2026 | | Linux | linux Debian 14 | 6.19.11-1 | [DEBIAN-CVE-2026-31507](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31507.md) | May 15, 2026 | --- Data as of 2026-11-09T01:18:40Z UTC. 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