NVD / CVE Program· CNA Linux

CVE-2026-45837: bpf: Fix use-after-free in arena_vm_close on fork

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: 0.11% (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 201128fcc7b213d27ab77bc4e89488b41796480f, 4fddde2a732de60bb97e3307d4eb69ac5f1d2b74, 723b9fa930cc277c15ce6b9ec9feec828cfac9d7.

Low priority for now. Upgrade to Linux Linux 201128fcc7b213d27ab77bc4e89488b41796480f, 4fddde2a732de60bb97e3307d4eb69ac5f1d2b74, 723b9fa930cc277c15ce6b9ec9feec828cfac9d7 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: bpf: Fix use-after-free in arena_vm_close on fork arena_vm_open() only bumps vml->mmap_count but never registers the child VMA in arena->vma_list. The vml->vma always points at the parent VMA, so after parent munmap the pointer dangles. If the child then calls bpf_arena_free_pages(), zap_pages() reads the stale vml->vma triggering use-after-free. Fix this by preventing the arena VMA from being inherited across fork with VM_DONTCOPY, and preventing VMA splits via the may_split callback. Also reject mremap with a .mremap callback returning -EINVAL. A same-size mremap(MREMAP_FIXED) on the full arena VMA reaches copy_vma() through the following path: check_prep_vma() - returns 0 early: new_len == old_len skips VM_DONTEXPAND check prep_move_vma() - vm_start == old_addr and vm_end == old_addr + old_len so may_split is never called move_vma() copy_vma_and_data() copy_vma() vm_area_dup() - copies vm_private_data (vml pointer) vm_ops->open() - bumps vml->mmap_count vm_ops->mremap() - returns -EINVAL, rollback unmaps new VMA The refcount ensures the rollback's arena_vm_close does not free the vml shared with the original VMA.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

openSUSE-SU-2026:10954-1

Published: May 27, 2026
Updated: Jun 26, 2026
EPSS: 0.1% · 1th percentile
CWE: CWE-416

Report tools

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Action score

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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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel6.9 and later · before 6.12.88
linux linux kernel6.13 and later · before 6.18.30
linux linux kernel6.19 and later · before 7.0.7

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
- 6.9affected
- 317460317a02a1af512697e6e964298dedd8a163 and later · before 723b9fa930cc277c15ce6b9ec9feec828cfac9d7affected · git
- 317460317a02a1af512697e6e964298dedd8a163 and later · before d18099f19e53250f8ad2801498b88cec29d9107aaffected · git
- 317460317a02a1af512697e6e964298dedd8a163 and later · before 201128fcc7b213d27ab77bc4e89488b41796480faffected · git
- 317460317a02a1af512697e6e964298dedd8a163 and later · before 4fddde2a732de60bb97e3307d4eb69ac5f1d2b74affected · git
- before 6.9not affected · semver
- 6.12.88 and later · up to and including 6.12.*not affected · semver
- 6.18.30 and later · up to and including 6.18.*not affected · semver
- 7.0.7 and later · up to and including 7.0.*not affected · semver
- 7.1 and laternot affected · original_commit_for_fix

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:13	linux	before 6.12.88-1	6.12.88-1
Debian:14	linux	before 7.0.7-1	7.0.7-1
openSUSE:Tumbleweed	kernel-source	before 7.0.11-1.1	7.0.11-1.1

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
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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-2026-45835May 26, 2026 · Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_new_connection_cb()
22Monitor
← EarlierCVE-2026-45836May 26, 2026 · Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_get_sndtimeo_cb()
22Monitor
Later →CVE-2026-45845May 27, 2026 · net/sched: taprio: fix NULL pointer dereference in class dump
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 / package	Fixed version	Source
Linux Linux	201128fcc7b213d27ab77bc4e89488b41796480f	Vendor (CNA)
Linux Linux	4fddde2a732de60bb97e3307d4eb69ac5f1d2b74	Vendor (CNA)
Linux Linux	723b9fa930cc277c15ce6b9ec9feec828cfac9d7	Vendor (CNA)
Linux Linux	d18099f19e53250f8ad2801498b88cec29d9107a	Vendor (CNA)
debian:linux	6.12.88-1 · Debian:13	Package registry (OSV)
opensuse:kernel-source	7.0.11-1.1 · openSUSE:Tumbleweed	Package 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

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)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

git.kernel.org/stable/c/201128fcc7b213d27ab77bc4e89488b41796480f

Show all references (3 more)

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

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