Answer in brief
CVE-2026-93100 records a Unknown severity vulnerability in fs/resctrl: Prevent use-after-free in rdtgroup_kn_put(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <ae69f936e8ffed553d899ba4c02f8a7461a89e54 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <4c593c62c1499665baebbb41b70e2c9b7e947b86 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <f5bcf539484d2d604c2f2330e09487ea090b21c7 || d20edc0bca5577bab38acb5b190619c922ddebf8 || 1b006f8cbde9f3dabdfafe2ff7aa9f831ed5b625 || 40300f986e47dbc8f1d02e5080385f5cf9f85f70 || b5a4949897ebada8132d54c93208989482503103 || >=4.14.170 <4.15 || >=4.19.102 <4.20 || >=5.4.18 <5.5 || >=5.5.2 <5.6 | ae69f936e8ffed553d899ba4c02f8a7461a89e54, 4c593c62c1499665baebbb41b70e2c9b7e947b86, f5bcf539484d2d604c2f2330e09487ea090b21c7, 4.15, 4.20, 5.5, 5.6 |
| Linux/Linuxgeneric | 5.6 | Not reported |
| Linux/Linuxgeneric | >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <971b40e3ca1279ca4917889e0195d33b66d071a4 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <828ff461c136b95d13b8d712c0a7a06a640e313a || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <ae69f936e8ffed553d899ba4c02f8a7461a89e54 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <4c593c62c1499665baebbb41b70e2c9b7e947b86 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <f5bcf539484d2d604c2f2330e09487ea090b21c7 || d20edc0bca5577bab38acb5b190619c922ddebf8 || 1b006f8cbde9f3dabdfafe2ff7aa9f831ed5b625 || 40300f986e47dbc8f1d02e5080385f5cf9f85f70 || b5a4949897ebada8132d54c93208989482503103 || >=4.14.170 <4.15 || >=4.19.102 <4.20 || >=5.4.18 <5.5 || >=5.5.2 <5.6 | 971b40e3ca1279ca4917889e0195d33b66d071a4, 828ff461c136b95d13b8d712c0a7a06a640e313a, ae69f936e8ffed553d899ba4c02f8a7461a89e54, 4c593c62c1499665baebbb41b70e2c9b7e947b86, f5bcf539484d2d604c2f2330e09487ea090b21c7, 4.15, 4.20, 5.5, 5.6 |
| Linux/Linuxgeneric | >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <906b3044dbf7c38cc411f7cf457c811363161e3b || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <971b40e3ca1279ca4917889e0195d33b66d071a4 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <828ff461c136b95d13b8d712c0a7a06a640e313a || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <ae69f936e8ffed553d899ba4c02f8a7461a89e54 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <4c593c62c1499665baebbb41b70e2c9b7e947b86 || >=b8511ccc75c033f6d54188ea4df7bf1e85778740 <f5bcf539484d2d604c2f2330e09487ea090b21c7 || d20edc0bca5577bab38acb5b190619c922ddebf8 || 1b006f8cbde9f3dabdfafe2ff7aa9f831ed5b625 || 40300f986e47dbc8f1d02e5080385f5cf9f85f70 || b5a4949897ebada8132d54c93208989482503103 || >=4.14.170 <4.15 || >=4.19.102 <4.20 || >=5.4.18 <5.5 || >=5.5.2 <5.6 | 906b3044dbf7c38cc411f7cf457c811363161e3b, 971b40e3ca1279ca4917889e0195d33b66d071a4, 828ff461c136b95d13b8d712c0a7a06a640e313a, ae69f936e8ffed553d899ba4c02f8a7461a89e54, 4c593c62c1499665baebbb41b70e2c9b7e947b86, f5bcf539484d2d604c2f2330e09487ea090b21c7, 4.15, 4.20, 5.5, 5.6 |
Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 17, 2026
In the Linux kernel, the following vulnerability has been resolved: fs/resctrl: Prevent use-after-free in rdtgroup_kn_put() A struct rdtgroup is reference counted via rdtgroup::waitcount. Callers that need the structure to remain valid across a sleep (while waiting on acquiring rdtgroup_mutex) take a reference with rdtgroup_kn_get() and release it with rdtgroup_kn_put(). The release path is intended to serve as the fallback freer: if the count drops to zero and the group has already been marked RDT_DELETED, rdtgroup_kn_put() frees the structure. The bulk teardown paths free_all_child_rdtgrp() and rmdir_all_sub() resulting from a resctrl directory remove or resctrl fs unmount act as the primary freer: they hold rdtgroup_mutex and free each rdtgroup whose waitcount is zero, otherwise they set RDT_DELETED and leave the freeing to the last waiter. These two freers race. rdtgroup_kn_put() commits waitcount == 0 with atomic_dec_and_test() outside rdtgroup_mutex, then reads rdtgroup::flags. Between those two operations a concurrent caller of free_all_child_rdtgrp() or rmdir_all_sub() (which holds the mutex) can observe waitcount == 0 via atomic_read(), call rdtgroup_remove(), and kfree() the structure. The subsequent read of rdtgroup::flags in rdtgroup_kn_put() is then a use-after-free, and the structure may even be freed twice if the freed memory happens to satisfy the RDT_DELETED flag check. Replace the bare atomic_dec_and_test() with atomic_dec_and_mutex_lock() so that the decrement-to-zero takes rdtgroup_mutex before the count becomes globally visible. The inspection of rdtgroup::flags then runs under the same mutex held by the bulk freers, making the two paths mutually exclusive. The common case where the count does not reach zero remains lock-free. Defer kernfs_unbreak_active_protection() until after the mutex is dropped since kernfs active protections functionally wrap rdtgroup_mutex. Remove resource group, which in turn drops its kernfs reference, after kernfs protection is restored. [ bp: Split the commit messsages into smaller, easier-parseable paragraphs. ]
Quoted source text, attributed separately from HOL analysis.