CVE-2026-99126

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.

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EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213 https://git.kernel.org/stable/c/34fa3607b7604b3052b19cec8b0ad644818cdd2a https://git.kernel.org/stable/c/8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab https://git.kernel.org/stable/c/977dac6cc5531a8e058df05b6af94406b940cb9e https://git.kernel.org/stable/c/a7c3e1795e4fe5e6680cab7cd7eee0503b00a248 https://git.kernel.org/stable/c/b264d8422779d69febce914efc47a92a85cc382c https://git.kernel.org/stable/c/c11e435d334e4c311eaaf721e179a5ca6852c221 https://git.kernel.org/stable/c/f9d9e2dadc9fbdfe01aeb6581978c3b59092919e

Frequently Asked Questions

What is CVE-2026-99126? +

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.

How do I check if I'm vulnerable to CVE-2026-99126? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.