CVE-2026-31507: Linux kernel · net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in ae5575e660410c8d2c5d38fb28a0f37aea945676 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:00 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in ae5575e660410c8d2c5d38fb28a0f37aea945676, 98ba5cb274768146e25ffbfde47753652c1c20d3, 81acbd345d405994875d419d43b319fee0b9ad62 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
AI-suggested
A fix is available and has been applied in multiple Linux kernel commits. Users should update to a fixed kernel version containing these commits. The vendor advisory indicates that tee() and splice_pipe_to_pipe() calls that attempt to duplicate SMC splice buffers now return -EFAULT, preventing exploitation. Users needing to duplicate SMC socket data should switch to a copy-based read path as the duplication method is no longer supported. No additional mitigation is required beyond applying the official fix.
Description
CVE-2026-31507 is a high-severity use-after-free vulnerability in the Linux kernel's net/smc subsystem. It occurs due to a double-free of the smc_spd_priv structure when the tee() system call duplicates a splice pipe buffer. This leads to a kernel NULL pointer dereference and potential kernel panic. The flaw arises because the smc_spd_priv pointer is shared between the original and cloned pipe buffers without proper reference counting, causing smc_rx_pipe_buf_release() to free the same object twice. The vulnerability affects Linux kernel version 4.18 and has been fixed in multiple subsequent commits.
References
- git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5 (opens in a new tab)
- git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676 (opens in a new tab)
- git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3 (opens in a new tab)
- git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62 (opens in a new tab)
- git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126 (opens in a new tab)
- git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5 (opens in a new tab)
- git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a (opens in a new tab)
- git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)