Unscored severity · published Oct 28, 2026
CVE-2026-99126
s390/ctcm: Prevent XID null dereference
New
–
CVSS
–
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
s390/ctcm: Prevent XID null dereference
The mpc_validate_xid() function sets grp->saved_xid2->xid2_flag2 to 0x40
to signal XID validation error. If peer XID is NULL or r/w channel
pairing mismatch happens, grp->saved_xid2 is never initialized. An
attempt to set the flag in such case leads to NULL dereference.
Fix this by using the always available priv->xid->xid2_flag2 instead of
grp->saved_xid2->xid2_flag2 for validation errors.
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 before 34fa3607b7604b3052b19cec8b0ad644818cdd2a; 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 before 8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab; 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 before b264d8422779d69febce914efc47a92a85cc382c; 2.6.26 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-99126
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-99126
git.kernel.org
https://git.kernel.org/stable/c/34fa3607b7604b3052b19cec8b0ad644818cdd2a
git.kernel.org
https://git.kernel.org/stable/c/8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab
git.kernel.org
https://git.kernel.org/stable/c/b264d8422779d69febce914efc47a92a85cc382c
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