xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert
CVSS score
4.1
EPSS probability
%0.2
Risk score
0.0
Published
2 mo ago
Kanıt listesindeki ürün ve sürüm eşleşmesini kontrol edin; bazı varyantlar hâlâ etkileniyor olabilir.
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%53
Short explanation
A vulnerability in the Linux kernel's xfrm policy module allows a crash via memory corruption during xfrm_hash_rebuild under memory pressure, due to incorrect preallocation logic that skips inexact policies and leaves poisoned nodes. Patch status is UNKNOWN. Affected versions include those prior to d9d9cc21cc90014724a14c447e3d587be9447107.
This vulnerability enables deterministic kernel crashes under memory pressure, potentially leading to system instability or denial of service. It is critical for systems relying on xfrm policy handling and operating under memory-constrained conditions.
What should be done?
- Update to a patched kernel version
- Apply vendor-specific security updates
The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.
Chain of evidence and sources
Linux çekirdeğinin xfrm politikası modülüne ait bir eksiklik, bellek basıncı altında xfrm_hash_rebuild sırasında yanlış öncelikleme mantığı nedeniyle inexact politikaları atlayarak ve bozulmuş düğümler bırakarak bir çöküş oluşturur.
Bu eksiklik, d9d9cc21cc90014724a14c447e3d587be9447107 sürümünden önceki Linux çekirdeği sürümlerinde etkilenir ve belirli sürüm aralıkları tanımlanmıştır.
Yama durumu BİLİNMEYEN; resmî kaynaklarda bir düzeltme ya da düzeltme olmamasının doğrulanması yapılmamıştır.
Show the technical text from the sources
In the Linux kernel, the following vulnerability has been resolved: xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert xfrm_hash_rebuild()'s first loop preallocates the bins/chains the reinsert loop needs, so the reinsert (after hlist_del_rcu()) cannot allocate or fail. But its guard is inverted: it skips policies with prefixlen < threshold and preallocates for the rest. prefixlen < threshold is exactly when policy_hash_bysel() returns NULL and the reinsert takes the allocating xfrm_policy_inexact_insert() path. So the loop preallocates for the exact policies (which never allocate) and skips the inexact ones, whose bin/node is then allocated GFP_ATOMIC during reinsert. On failure the error path only WARN_ONCE()s and continues, leaving a poisoned bydst node; the next rebuild's hlist_del_rcu() dereferences LIST_POISON2 and takes a GPF. Reachable under memory pressure, deterministic via failslab. Invert the guard so preallocation covers exactly the reinserted policies; the reinsert then allocates nothing and cannot fail. Crash: Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdead...] ... Workqueue: events xfrm_hash_rebuild RIP: 0010:xfrm_hash_rebuild+0x5b3/0x1190 RAX: dead000000000122 (LIST_POISON2 + offset) ... Call Trace: hlist_del_rcu (include/linux/rculist.h:599) xfrm_hash_rebuild (net/xfrm/xfrm_policy.c:1365) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) ... Kernel panic - not syncing: Fatal exception in interrupt
CVSS vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
Explanation produced with the local qwen3:4b-instruct model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-64579 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 4.1 | CVSS 3.x | — | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H | Microsoft MSRC |
Patch and Remediation Guide
Solution & Remediation Advisory
2 düzeltme kanıtı bulundu; en az 4 ürün veya sürüm hâlâ etkileniyor ya da inceleniyor.
7.1.6-1Debian sid: 7.1.6-1
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64579 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-64579 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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