Linux: Use After Free
CVE-2026-31419 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 060d83bb6147c36fc21134d5b332d266b8c176bc, df690112b2172e8eb0f4dd8ec1019b65ee979203, 00752893f96b344f258c9c6de18b33171ac4872c as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 060d83bb6147c36fc21134d5b332d266b8c176bc or df690112b2172e8eb0f4dd8ec1019b65ee979203 or 00752893f96b344f258c9c6de18b33171ac4872c or 2de5c8eea0a9db99dae7c36f4b541b74b41d3a04, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.11 or 5.16 or 5.17 or 6.12.86, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 20949c3816463e97c6f8fe84c0280c7e5ae83a8d up to, but not including, 060d83bb6147c36fc21134d5b332d266b8c176bc; f1d206181f19b00b275b258fea1418718a2f4173 up to, but not including, df690112b2172e8eb0f4dd8ec1019b65ee979203; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, 00752893f96b344f258c9c6de18b33171ac4872c; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, 2de5c8eea0a9db99dae7c36f4b541b74b41d3a04; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, a0f661918edc79d7a75e468128af8d41e2a1a83a; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, d4cc7e4c80b1634c7b1497574a2fdb18df6c026c; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, f5b94654a4a19891a8108d66ef166de6c028c6cd; 4e5bd03ae34652cd932ab4c91c71c511793df75c up to, but not including, 2884bf72fb8f03409e423397319205de48adca16; and 5 more ranges | 060d83bb6147c36fc21134d5b332d266b8c176bc, df690112b2172e8eb0f4dd8ec1019b65ee979203, 00752893f96b344f258c9c6de18b33171ac4872c, 2de5c8eea0a9db99dae7c36f4b541b74b41d3a04, a0f661918edc79d7a75e468128af8d41e2a1a83a, d4cc7e4c80b1634c7b1497574a2fdb18df6c026c |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 5.10.94 up to, but not including, 5.11; 5.15.17 up to, but not including, 5.16; 5.16.3 up to, but not including, 5.17; 5.17 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.0 | 5.11, 5.16, 5.17, 6.12.86, 6.18.22, 6.19.12 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.0 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: net: bonding: fix use-after-free in bond_xmit_broadcast() bond_xmit_broadcast() reuses the original skb for the last slave (determined by bond_is_last_slave()) and clones it for others. Concurrent slave enslave/release can mutate the slave list during RCU-protected iteration, changing which slave is "last" mid-loop. This causes the original skb to be double-consumed (double-freed). Replace the racy bond_is_last_slave() check with a simple index comparison (i + 1 == slaves_count) against the pre-snapshot slave count taken via READ_ONCE() before the loop. This preserves the zero-copy optimization for the last slave while making the "last" determination stable against concurrent list mutations. The UAF can trigger the following crash: ================================================================== BUG: KASAN: slab-use-after-free in skb_clone Read of size 8 at addr ffff888100ef8d40 by task exploit/147 CPU: 1 UID: 0 PID: 147 Comm: exploit Not tainted 7.0.0-rc3+ #4 PREEMPTLAZY Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:597) skb_clone (include/linux/skbuff.h:1724 include/linux/skbuff.h:1792 include/linux/skbuff.h:3396 net/core/skbuff.c:2108) bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5334) bond_start_xmit (drivers/net/bonding/bond_main.c:5567 drivers/net/bonding/bond_main.c:5593) dev_hard_start_xmit (include/linux/netdevice.h:5325 include/linux/netdevice.h:5334 net/core/dev.c:3871 net/core/dev.c:3887) __dev_queue_xmit (include/linux/netdevice.h:3601 net/core/dev.c:4838) ip6_finish_output2 (include/net/neighbour.h:540 include/net/neighbour.h:554 net/ipv6/ip6_output.c:136) ip6_finish_output (net/ipv6/ip6_output.c:208 net/ipv6/ip6_output.c:219) ip6_output (net/ipv6/ip6_output.c:250) ip6_send_skb (net/ipv6/ip6_output.c:1985) udp_v6_send_skb (net/ipv6/udp.c:1442) udpv6_sendmsg (net/ipv6/udp.c:1733) __sys_sendto (net/socket.c:730 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) </TASK> Allocated by task 147: Freed by task 147: The buggy address belongs to the object at ffff888100ef8c80 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 192 bytes inside of freed 224-byte region [ffff888100ef8c80, ffff888100ef8d60) Memory state around the buggy address: ffff888100ef8c00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff888100ef8c80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888100ef8d00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888100ef8d80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888100ef8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- git.kernel.org/stable/c/00752893f96b344f258c9c6de18b33171ac4872c
- git.kernel.org/stable/c/060d83bb6147c36fc21134d5b332d266b8c176bc
- git.kernel.org/stable/c/2de5c8eea0a9db99dae7c36f4b541b74b41d3a04
- git.kernel.org/stable/c/a0f661918edc79d7a75e468128af8d41e2a1a83a
- git.kernel.org/stable/c/df690112b2172e8eb0f4dd8ec1019b65ee979203
- access.redhat.com/errata/RHSA-2026:13566
- access.redhat.com/errata/RHSA-2026:19521
- access.redhat.com/errata/RHSA-2026:21209
- access.redhat.com/errata/RHSA-2026:22334
- access.redhat.com/errata/RHSA-2026:22900
- access.redhat.com/errata/RHSA-2026:22940
- access.redhat.com/errata/RHSA-2026:23224
- access.redhat.com/errata/RHSA-2026:25191
- access.redhat.com/errata/RHSA-2026:25217
- access.redhat.com/errata/RHSA-2026:27353
Recent Use After Free vulnerabilities
- 8.1 High severity
- 8.4 High severity
- 7.0 High severity
- 9.6 Critical severity
- 7.8 High severity
- 8.8 High severity
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