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NVD / CVE Program· CNA Linux

CVE-2025-21866: powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.25% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 2d542f13d26344e3452eee77613026ce9b653065, 2e6c80423f201405fd65254e52decd21663896f3, 6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4c; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.82.1-1.

Low priority for now. Upgrade to Linux Linux 2d542f13d26344e3452eee77613026ce9b653065, 2e6c80423f201405fd65254e52decd21663896f3, 6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4c; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.82.1-1 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: powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC Erhard reported the following KASAN hit while booting his PowerMac G4 with a KASAN-enabled kernel 6.13-rc6: BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8 Write of size 8 at addr f1000000 by task chronyd/1293 CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G W 6.13.0-rc6-PMacG4 #2 Tainted: [W]=WARN Hardware name: PowerMac3,6 7455 0x80010303 PowerMac Call Trace: [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable) [c24375b0] [c0504998] print_report+0xdc/0x504 [c2437610] [c050475c] kasan_report+0xf8/0x108 [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8 [c24376c0] [c004c014] patch_instructions+0x15c/0x16c [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478 [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14 [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4 [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890 [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420 [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c --- interrupt: c00 at 0x5a1274 NIP: 005a1274 LR: 006a3b3c CTR: 005296c8 REGS: c2437f40 TRAP: 0c00 Tainted: G W (6.13.0-rc6-PMacG4) MSR: 0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI> CR: 24004422 XER: 00000000 GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932 GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57 GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002 GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001 NIP [005a1274] 0x5a1274 LR [006a3b3c] 0x6a3b3c --- interrupt: c00 The buggy address belongs to the virtual mapping at [f1000000, f1002000) created by: text_area_cpu_up+0x20/0x190 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30 flags: 0x80000000(zone=2) raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001 raw: 00000000 page dumped because: kasan: bad access detected Memory state around the buggy address: f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== f8 corresponds to KASAN_VMALLOC_INVALID which means the area is not initialised hence not supposed to be used yet. Powerpc text patching infrastructure allocates a virtual memory area using get_vm_area() and flags it as VM_ALLOC. But that flag is meant to be used for vmalloc() and vmalloc() allocated memory is not supposed to be used before a call to __vmalloc_node_range() which is never called for that area. That went undetected until commit e4137f08816b ("mm, kasan, kmsan: instrument copy_from/to_kernel_nofault") The area allocated by text_area_cpu_up() is not vmalloc memory, it is mapped directly on demand when needed by map_kernel_page(). There is no VM flag corresponding to such usage, so just pass no flag. That way the area will be unpoisonned and usable immediately.

Published
Mar 12, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 16th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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.

VendorProduct
linuxlinux kernel

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

    • 4.13affected
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before 97de5852058a299ba447cd9782fe96488d30108baffected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before f8d4c5b653c1bc0df56e15658bbf64fc359adc4eaffected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before 6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4caffected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before c905a3053518212a1017e50bd2be3bee59305bb0affected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before 2d542f13d26344e3452eee77613026ce9b653065affected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before 8d06e9208184b2851fa79a3a39d6860320c8bdf8affected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before 2e6c80423f201405fd65254e52decd21663896f3affected · git
    • 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 and later · before d262a192d38e527faa5984629aabda2e0d1c4f54affected · git
    • before 4.13not affected · semver
Affected versions · NVD (5)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.13 and later · before 6.1.130
  • linux linux kernel6.2 and later · before 6.6.80
  • linux linux kernel6.7 and later · before 6.12.17
  • linux linux kernel6.13 and later · before 6.13.5
  • linux linux kernel6.14

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.133-16.1.133-1
Debian:13linuxbefore 6.12.17-16.12.17-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-21857Mar 12, 2025 · net/sched: cls_api: fix error handling causing NULL dereference
    22Monitor
  • ← EarlierCVE-2025-21860Mar 12, 2025 · mm/zswap: fix inconsistency when zswap_store_page() fails
    13Monitor
  • Later →CVE-2025-21844Mar 12, 2025 · smb: client: Add check for next_buffer in receive_encrypted_standard()
    22Monitor

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 Linux2d542f13d26344e3452eee77613026ce9b653065Vendor (CNA)
Linux Linux2e6c80423f201405fd65254e52decd21663896f3Vendor (CNA)
Linux Linux6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4cVendor (CNA)
Linux Linux8d06e9208184b2851fa79a3a39d6860320c8bdf8Vendor (CNA)
Linux Linux97de5852058a299ba447cd9782fe96488d30108bVendor (CNA)
Linux Linuxc905a3053518212a1017e50bd2be3bee59305bb0Vendor (CNA)
Linux Linuxd262a192d38e527faa5984629aabda2e0d1c4f54Vendor (CNA)
Linux Linuxf8d4c5b653c1bc0df56e15658bbf64fc359adc4eVendor (CNA)
azl3 kernel 6.6.78.1-3 on Azure Linux 3.06.6.82.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.133-1 · 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.

Variant candidates

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

  • CVE-2021-47137352 days apartnet: lantiq: fix memory corruption in RX ring
    39Monitor
  • CVE-2024-35969296 days apartipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr
    35Monitor
  • CVE-2024-34027261 days apartf2fs: compress: fix to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock
    31Monitor
  • CVE-2021-47551292 days apartdrm/amd/amdkfd: Fix kernel panic when reset failed and been triggered again
    31Monitor
  • CVE-2021-47130362 days apartnvmet: fix freeing unallocated p2pmem
    30Monitor
  • CVE-2024-26894329 days apartACPI: processor_idle: Fix memory leak in acpi_processor_power_exit()
    24Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

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

References

Show all references (8 more)

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

All records