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NVD / CVE Program· CNA Linux

CVE-2026-64579: xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 1cdeed9df1306f1a277e715600772640d63defa9, 43a4d510523779891cf8eca7ffb4a086b0b5d8bf, 6aa3796d18a9fda953ad76a62b57bf6c145cb9ef; azl3 kernel 6.6.145.2-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1cdeed9df1306f1a277e715600772640d63defa9, 43a4d510523779891cf8eca7ffb4a086b0b5d8bf, 6aa3796d18a9fda953ad76a62b57bf6c145cb9ef; azl3 kernel 6.6.145.2-1 on Azure Linux 3.0 6.6.150.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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

—No exploit Fix available
Published
Aug 5, 2026
Updated
Aug 19, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.0affected
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before e48f4c3e3df35b34be719d72d737bbeaca77cf0caffected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before 1cdeed9df1306f1a277e715600772640d63defa9affected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before 43a4d510523779891cf8eca7ffb4a086b0b5d8bfaffected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before d9d9cc21cc90014724a14c447e3d587be9447107affected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before 94c00391a5117530188334f740ce26d3f1256190affected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before 7acc5ed2f33608a3d83b64f50a5766843b6e2485affected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before 6aa3796d18a9fda953ad76a62b57bf6c145cb9efaffected · git
    • 24969facd704a5f0dd8e08da86bf32a9ce972bee and later · before f38f8cce2f7e79775b3db7e8a5eacda04ac908e4affected · git
    • before 5.0not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.101-1~deb12u16.12.101-1~deb12u1
Debian:13linuxbefore 6.12.101-16.12.101-1
Debian:14linuxbefore 7.1.6-17.1.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-64577Aug 5, 2026 · gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
    30Monitor
  • ← EarlierCVE-2026-64578Aug 5, 2026 · ksmbd: validate compound request size before reading StructureSize2
    32Monitor
  • Later →CVE-2026-64567Aug 5, 2026 · btrfs: reject free space cache with more entries than pages
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1cdeed9df1306f1a277e715600772640d63defa9Vendor (CNA)
Linux Linux43a4d510523779891cf8eca7ffb4a086b0b5d8bfVendor (CNA)
Linux Linux6aa3796d18a9fda953ad76a62b57bf6c145cb9efVendor (CNA)
Linux Linux7acc5ed2f33608a3d83b64f50a5766843b6e2485Vendor (CNA)
Linux Linux94c00391a5117530188334f740ce26d3f1256190Vendor (CNA)
Linux Linuxd9d9cc21cc90014724a14c447e3d587be9447107Vendor (CNA)
Linux Linuxe48f4c3e3df35b34be719d72d737bbeaca77cf0cVendor (CNA)
Linux Linuxf38f8cce2f7e79775b3db7e8a5eacda04ac908e4Vendor (CNA)
azl3 kernel 6.6.145.2-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.101-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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