Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: tracing: Avoid NULL return from hist_field_name() on truncation hist_field_name() returns "" everywhere except the fully-qualified VAR_REF/EXPR case, where snprintf() truncation returns NULL early and bypasses the bottom NULL->"" guard. Callers don't expect NULL: strcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758 and the strcmp() in the sort-key match loop at :4804 both deref it. system and event_name are bounded by MAX_EVENT_NAME_LEN, but the field name on a VAR_REF is kstrdup'd from a histogram variable name parsed out of the trigger string and has no length cap, so a long enough var name in a fully qualified reference can reach the truncation path. Keep the length check but leave field_name as "" on overflow.

Affected versions

Linux: 2e8578364061c4e88ae33bc20c2d6f64f365f6a2 through before e3f5d42cdc2f167719564693675f1eead81378ea (git); dfd1cd57ee6067301841b7b0967c70f910a51150 through before 37377b39ff86dacbc533275c1155210d4fd5dc91 (git); e5c223f46c2e0691461dd97510c15e1f77148872 through before 0402a1d3ddec565132867337ed44514a09d84728 (git); 9399a92989354e34086f9a5c379493217df83c5e through before e91687643c440ca3997d67646e6f80b92edc6703 (git); 3cb6cb9c5a547a1979ad74f38eefe8e3687d96e0 through before be4e99038c1603fa6b329d8ee3e364825e17c353 (git); 0402c60abe769098d77f3b3bd1e29a97922b614b through before d6c8b3ebdcdb12b59ad4212acb137cc56cae453d (git); 6929e650db8451a9975ac0a631ba2d6e5d1e80ba through before 915c1254fe0788abddc31095b360e9dc98907a34 (git); 5ec1d1e97de134beed3a5b08235a60fc1c51af96 through before 576ec047d20b368b43c4d5db98c4f2e0f3c101ec (git); 6.6.141 through before 6.6.142 (semver); 6.12.91 through before 6.12.92 (semver); 6.18.33 through before 6.18.34 (semver); 7.0.10 through before 7.0.11 (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.