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NVD / CVE Program· CNA Linux

CVE-2023-53487: powerpc/rtas_flash: allow user copy to flash block cache objects

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.16% (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 0ba7f969be599e21d4b1f1e947593de6515f4996, 1d29e21ed09fa668416fa7721e08d451b9903485, 4f3175979e62de3b929bfa54a0db4b87d36257a7.

Low priority for now. Upgrade to Linux Linux 0ba7f969be599e21d4b1f1e947593de6515f4996, 1d29e21ed09fa668416fa7721e08d451b9903485, 4f3175979e62de3b929bfa54a0db4b87d36257a7 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/rtas_flash: allow user copy to flash block cache objects With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the /proc/powerpc/rtas/firmware_update interface to prepare a system firmware update yields a BUG(): kernel BUG at mm/usercopy.c:102! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2 Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries NIP: c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000 REGS: c0000000148c76a0 TRAP: 0700 Not tainted (6.5.0-rc3+) MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002242 XER: 0000000c CFAR: c0000000001fbd34 IRQMASK: 0 [ ... GPRs omitted ... ] NIP usercopy_abort+0xa0/0xb0 LR usercopy_abort+0x9c/0xb0 Call Trace: usercopy_abort+0x9c/0xb0 (unreliable) __check_heap_object+0x1b4/0x1d0 __check_object_size+0x2d0/0x380 rtas_flash_write+0xe4/0x250 proc_reg_write+0xfc/0x160 vfs_write+0xfc/0x4e0 ksys_write+0x90/0x160 system_call_exception+0x178/0x320 system_call_common+0x160/0x2c4 The blocks of the firmware image are copied directly from user memory to objects allocated from flash_block_cache, so flash_block_cache must be created using kmem_cache_create_usercopy() to mark it safe for user access. [mpe: Trim and indent oops]

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 1, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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

Affected versions

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

  • linux linux kernel4.16 and later · before 4.19.293
  • linux linux kernel4.20 and later · before 5.4.255
  • linux linux kernel5.5 and later · before 5.10.192
  • linux linux kernel5.11 and later · before 5.15.128
  • linux linux kernel5.16 and later · before 6.1.47
  • linux linux kernel6.2 and later · before 6.4.12
  • linux linux kernel6.5

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

    • 4.16affected
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 8f09cc15dcd91d16562400c51d24c7be0d5796faaffected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 1d29e21ed09fa668416fa7721e08d451b9903485affected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 0ba7f969be599e21d4b1f1e947593de6515f4996affected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 8ef25fb13494e35c6dbe15445c7875fa92bc3e8baffected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before b8fee83aa4ed3846c7f50a0b364bc699f48d96e5affected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 6acb8a453388374fafb3c3b37534b675b2aa0ae1affected · git
    • 6d07d1cd300f4c7e16005f881fea388164999cc8 and later · before 4f3175979e62de3b929bfa54a0db4b87d36257a7affected · git
    • before 4.16not affected · semver
    • 4.19.293 and later · up to and including 4.19.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.52-16.1.52-1
Debian:13linuxbefore 6.4.13-16.4.13-1

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-2023-53485Oct 1, 2025 · fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev
    31Monitor
  • ← EarlierCVE-2023-53486Oct 1, 2025 · fs/ntfs3: Enhance the attribute size check
    28Monitor
  • Later →CVE-2023-53488Oct 1, 2025 · IB/hfi1: Fix possible panic during hotplug remove
    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 Linux0ba7f969be599e21d4b1f1e947593de6515f4996Vendor (CNA)
Linux Linux1d29e21ed09fa668416fa7721e08d451b9903485Vendor (CNA)
Linux Linux4f3175979e62de3b929bfa54a0db4b87d36257a7Vendor (CNA)
Linux Linux6acb8a453388374fafb3c3b37534b675b2aa0ae1Vendor (CNA)
Linux Linux8ef25fb13494e35c6dbe15445c7875fa92bc3e8bVendor (CNA)
Linux Linux8f09cc15dcd91d16562400c51d24c7be0d5796faVendor (CNA)
Linux Linuxb8fee83aa4ed3846c7f50a0b364bc699f48d96e5Vendor (CNA)
debian:linux6.1.52-1 · 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.

No history yet (it accumulates with the daily EPSS job).

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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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).

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

Weakness class (CWE)

—

CVSS vector

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

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

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

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

All records