CVE-2026-99126

s390/ctcm: Prevent XID null dereference

State: Published
Severity: Not scored
Published: Oct 28, 2026
Updated: Oct 30, 2026
Reserved: Sep 25, 2026

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before f9d9e2dadc9fbdfe01aeb6581978c3b59092919eAffected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before a7c3e1795e4fe5e6680cab7cd7eee0503b00a248Affected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before c11e435d334e4c311eaaf721e179a5ca6852c221Affected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 977dac6cc5531a8e058df05b6af94406b940cb9eAffected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213Affected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 34fa3607b7604b3052b19cec8b0ad644818cdd2aAffected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeabAffected 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before b264d8422779d69febce914efc47a92a85cc382cAffected
LinuxLinux	2.6.26Affected before 2.6.26Not affected 5.10.273 through 5.10.Not affected 5.15.224 through 5.15.Not affected 6.1.191 through 6.1.Not affected 6.6.161 through 6.6.Not affected 6.12.115 through 6.12.Not affected 6.18.59 through 6.18.Not affected 7.2.13 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before f9d9e2dadc9fbdfe01aeb6581978c3b59092919eAffected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before a7c3e1795e4fe5e6680cab7cd7eee0503b00a248Affected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before c11e435d334e4c311eaaf721e179a5ca6852c221Affected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 977dac6cc5531a8e058df05b6af94406b940cb9eAffected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213Affected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 34fa3607b7604b3052b19cec8b0ad644818cdd2aAffected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before 8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeabAffected
293d984f0e3604c04dcdbf00117ddc1e5d4b1909 to before b264d8422779d69febce914efc47a92a85cc382cAffected

LinuxLinux

2.6.26Affected
before 2.6.26Not affected
5.10.273 through 5.10.*Not affected
5.15.224 through 5.15.*Not affected
6.1.191 through 6.1.*Not affected
6.6.161 through 6.6.*Not affected
6.12.115 through 6.12.*Not affected
6.18.59 through 6.18.*Not affected
7.2.13 through 7.2.*Not affected
7.3 and laterNot affected

References

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