CVE-2026-98230

xfrm: use hlist_del_init_rcu for state_cache and state_cache_input

Published Oct 6, 2026 CVSS 3.1 · 7 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

xfrm: use hlist_del_init_rcu for state_cache and state_cache_input

Commit 14acf9652e56 ("xfrm: defensively unhash xfrm_state lists in
__xfrm_state_delete") converted bydst/bysrc/byseq/byspi from
hlist_del_rcu() to hlist_del_init_rcu() so that a second
__xfrm_state_delete() on the same object becomes a no-op rather than a
write through LIST_POISON pprev. It missed state_cache and
state_cache_input, which kept hlist_del_rcu():

- hlist_del_rcu() leaves pprev = LIST_POISON2 (non-NULL), so
hlist_unhashed() returns false.
- hlist_del_init_rcu() leaves pprev = NULL, so hlist_unhashed()
returns true.

A second __xfrm_state_delete() therefore enters __hlist_del() on the
already-deleted state_cache/state_cache_input nodes and does
WRITE_ONCE(*pprev, next) through LIST_POISON2 — a write use-after-free
once the slab is reused. The corruption can in turn cause a subsequent
hlist_for_each_entry_rcu traversal to follow a dangling next pointer,
producing the read use-after-free reported in xfrm_input_state_lookup().

Switch state_cache and state_cache_input to hlist_del_init_rcu() to
match the other four lists, closing the write use-after-free and, with
it, the read use-after-free it spawns.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4850-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6568-1 linux security update
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9022-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9023-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9039-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9091-1 Linux kernel (NVIDIA Tegra) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: xfrm: use hlist_del_init_rcu for state_cache and state_cache_input Commit 14acf9652e56 ("xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete") converted bydst/bysrc/byseq/byspi from hlist_del_rcu() to hlist_del_init_rcu() so that a second __xfrm_state_delete() on the same object becomes a no-op rather than a write through LIST_POISON pprev. It missed state_cache and state_cache_input, which kept hlist_del_rcu(): - hlist_del_rcu() leaves pprev = LIST_POISON2 (non-NULL), so hlist_unhashed() returns false. - hlist_del_init_rcu() leaves pprev = NULL, so hlist_unhashed() returns true. A second __xfrm_state_delete() therefore enters __hlist_del() on the already-deleted state_cache/state_cache_input nodes and does WRITE_ONCE(*pprev, next) through LIST_POISON2 — a write use-after-free once the slab is reused. The corruption can in turn cause a subsequent hlist_for_each_entry_rcu traversal to follow a dangling next pointer, producing the read use-after-free reported in xfrm_input_state_lookup(). Switch state_cache and state_cache_input to hlist_del_init_rcu() to match the other four lists, closing the write use-after-free and, with it, the read use-after-free it spawns.
Title xfrm: use hlist_del_init_rcu for state_cache and state_cache_input
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:16 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 6, 2026, 9:18 AM
Modified
Oct 19, 2026, 10:18 AM
Severity
Moderate
Public date
Oct 6, 2026, 12:00 AM